Blake Lively shared a touching tribute to her Gossip Girl co-star Michelle Trachtenberg on Wednesday, following her sudden death at 39.

Reflecting on their first day together on the set of the CW series, Lively, 37, posted a photo of Michelle, whom she described as ‘fiercely loyal,’ ‘kind,’ and ‘deeply sensitive.’

‘This is the first day I met Michelle. She was electricity. You knew when she entered a room because the vibration changed,’ Lively stated in her lengthy Instagram tribute.

Lively emphasized Michelle’s authenticity, writing, ‘Everything she did, she did 200%. She laughed the fullest at someone’s joke, she faced authority head on when she felt something was wrong, she cared deeply about her work.’

The It Ends With Us Star said Michelle, who portrayed Georgina Sparks on the show, ‘was proud to be a part of this community and industry as painful as it could be sometimes’ and ‘was fiercely loyal to her friends and brave for those she loved.’

Trachtenberg was found dead by her mother on Wednesday in her New York City apartment.

The actress died of natural causes and may have suffered complications following a liver transplant, police sources told ABC News.

Blake Lively, 37, shared a touching tribute to her Gossip Girl co-star Michelle Trachtenberg on Wednesday, following her sudden death at 39; the two seen in 2009
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Blake Lively, 37, shared a touching tribute to her Gossip Girl co-star Michelle Trachtenberg on Wednesday, following her sudden death at 39; the two seen in 2009

Reflecting on their first day together on the set of the CW series, Lively posted a photo of Michelle, whom she described as 'fiercely loyal,' 'kind,' and 'deeply sensitive'
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Reflecting on their first day together on the set of the CW series, Lively posted a photo of Michelle, whom she described as ‘fiercely loyal,’ ‘kind,’ and ‘deeply sensitive’

‘She was big and bold and distinctly herself,’ Lively — who played Serena van der Woodsen on the series from 2008-2012 — added in her tribute.

The star then shared an anecdote about Michelle’s lipgloss.

She recounted how Michelle ‘always had yummy caramel smelling lipgloss on because she didn’t just want to sparkle on camera, she liked creating a nice experience for anyone who was in her orbit, even down to the subtle smell of her lipgloss because she cared about the sweet details.’

Lively described her as a ‘kind person, through and through.’

Reflecting on the loss, she added: ‘Time passes. You take for granted that you get the chance to see an old friend. To paraphrase, the real tragedies in life are the ones that blindside you on an idle Tuesday.’

She concluded her tribute by urging her fans: ‘Hold those you love and have loved dear. The world lost a deeply sensitive and good person in Michelle. May her work and her huge heart be remembered by those who were lucky to experience her fire.’

Michelle’s other Gossip Girl co-star, Ed Westwick, also expressed his condolences on Instagram, writing, ‘So sad to hear of the passing of @michelletrachtenberg. Sending prayers.’

Trachtenberg had a recurring role as ‘The Witch of the Upper East Side’, Georgina Sparks, in 28 episodes of The Gossip Girl spanning 2008-2012.

The show followed a group of wealthy teenagers attending prestigious private schools, while navigating friendships, rivalries, and relationships.

'Everything she did, she did 200%. She laughed the fullest at someone's joke, she faced authority head on when she felt something was wrong, she cared deeply about her work,' Lively wrote; the two seen in a still from Gossip Girl
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‘Everything she did, she did 200%. She laughed the fullest at someone’s joke, she faced authority head on when she felt something was wrong, she cared deeply about her work,’ Lively wrote; the two seen in a still from Gossip Girl

Lively said Michelle 'was fiercely loyal to her friends and brave for those she loved'; Seen with her Gossip Girl co-stars in 2010. (L-R) Jessica Szohr, Lively, Leighton Meester, costume designer Eric Daman, Trachtenberg, Ed Westwick and Sebastian Stan
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Lively said Michelle ‘was fiercely loyal to her friends and brave for those she loved’; Seen with her Gossip Girl co-stars in 2010. (L-R) Jessica Szohr, Lively, Leighton Meester, costume designer Eric Daman, Trachtenberg, Ed Westwick and Sebastian Stan

She concluded her tribute writing, 'May her work and her huge heart be remembered by those who were lucky to experience her fire'; Trachtenberg pictured with Lively and her ex-boyfriend, and Gossip Girl co-star, Penn, in 2010
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She concluded her tribute writing, ‘May her work and her huge heart be remembered by those who were lucky to experience her fire’; Trachtenberg pictured with Lively and her ex-boyfriend, and Gossip Girl co-star, Penn, in 2010

Just weeks before her death, Trachtenberg slammed a fan question about Lively's ongoing legal war with her It Ends With Us co-star and director, Justin Baldoni, 41
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Just weeks before her death, Trachtenberg slammed a fan question about Lively’s ongoing legal war with her It Ends With Us co-star and director, Justin Baldoni, 41

After a fan asked her opinion on the legal battle in her Instagram comments, she wrote: 'Gosh. Im busy worrying about real world news and families who have no home anymore from the LA fires. But you do you'
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After a fan asked her opinion on the legal battle in her Instagram comments, she wrote: ‘Gosh. Im busy worrying about real world news and families who have no home anymore from the LA fires. But you do you’

Lively and Baldoni have engaged in numerous lawsuits related to their collaboration on the 2024 film It Ends With Us; Baldoni seen in 2024
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Lively and Baldoni have engaged in numerous lawsuits related to their collaboration on the 2024 film It Ends With Us; Baldoni seen in 2024

The wildly popular CW show has experienced a Gen Z resurgence in recent years thanks to Netflix.

Michelle also appeared in two episodes of the Gossip Girl reboot on Max in 2022, reprising her role of Georgina.

Just weeks before her death, Trachtenberg slammed a fan question about Lively’s ongoing legal war with her It Ends With Us co-star and director, Justin Baldoni, 41.

She shared a photo of herself to Instagram on January 16, wearing sunglasses and posing with her arms crossed.

‘It takes a lot of strength to see through all the bulls**t. And some dark sunglasses. #newyork,’ she captioned the photo.

In her comments, one person wrote: ‘Would love to see you release a statement on the Blake drama ❤️ Or idk if this is a direct statement? Hahaha you’re so fabulous.’

Trachtenberg wrote back, ‘gosh. Im busy worrying about real world news and families who have no home anymore from the LA fires. But you do you.’

Lively and Baldoni have engaged in numerous lawsuits related to their collaboration on the 2024 film It Ends With Us.

Michelle's other Gossip Girl co-star, Ed Westwick, also expressed his condolences on Instagram, writing, 'So sad to hear of the passing of @michelletrachtenberg. Sending prayers'
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Michelle’s other Gossip Girl co-star, Ed Westwick, also expressed his condolences on Instagram, writing, ‘So sad to hear of the passing of @michelletrachtenberg. Sending prayers’

Trachtenberg had a recurring role as 'The Witch of the Upper East Side', Georgina Sparks, in 28 episodes of Gossip Girl, spanning 2008-2012; seen in a still
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Trachtenberg had a recurring role as ‘The Witch of the Upper East Side’, Georgina Sparks, in 28 episodes of Gossip Girl, spanning 2008-2012; seen in a still

The show followed a group of wealthy teenagers attending prestigious private schools, while navigating friendships, rivalries, and relationships
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The show followed a group of wealthy teenagers attending prestigious private schools, while navigating friendships, rivalries, and relationships

In 2022, Michelle reprised her role as the wedding-spoiling, manipulative socialite in two episodes of the second (and final) season of HBO Max's Gossip Girl reboot; seen in a still
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In 2022, Michelle reprised her role as the wedding-spoiling, manipulative socialite in two episodes of the second (and final) season of HBO Max’s Gossip Girl reboot; seen in a still

On the same day Trachtenberg shared her Instagram post, Baldoni filed a defamation lawsuit against Lively and her husband, Ryan Reynolds.

This followed Lively’s own lawsuit against Baldoni on December 20, 2024, where she alleged ‘disturbing’ and ‘unprofessional’ behavior during the filming of the movie.

Police told DailyMail.com that there is no foul play suspected in Trachtenberg’s death. Sources told TMZ that the actress had been battling alcohol issues.

An autopsy will be carried out by the medical examiner’s office to establish the exact cause of death.

‘On Wednesday, February 26, 2025, at approximately 0801 hours, police responded to a 911 call of an aided individual at 1 Columbus Place, within the confines of the Midtown North Precinct,’ police said in a statement.

‘Upon arrival, officers observed a 39-year-old female unconscious and unresponsive. EMS responded to the location and pronounced the victim deceased.

‘Criminality is not suspected. The Medical Examiner will determine the cause of death. The investigation remains ongoing.’

Patients can receive a liver transplant after damaging the vital organ through alcohol abuse, hepatitis C or liver disease.

Anyone who’s received a liver transplant due to alcohol abuse is advised to abstain from alcohol afterwards.

Trachtenberg was best known for her on role teen supernatural drama Buffy the Vampire Slayer spanning 2000-2003.

Trachtenberg was found dead on Wednesday in her New York City apartment. The actress died of natural causes and may have suffered complications following a liver transplant; seen in 2020
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Trachtenberg was found dead on Wednesday in her New York City apartment. The actress died of natural causes and may have suffered complications following a liver transplant; seen in 2020

In recent years Trachtenberg had sparked concern for her health after sharing troubling social media posts in which she looked frail
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In recent years Trachtenberg had sparked concern for her health after sharing troubling social media posts in which she looked frail

She played Buffy’s younger sister Dawn Summers in 66 episodes of the hit show.

She also appeared in the 1996 film Harriet the Spy when she was 10 years old, alongside Rosie O’Donnell.

In recent years Trachtenberg had sparked concern for her health after sharing troubling social media posts in which she looked frail.

The former child star grew up in New York.

Her mother Lana and sister Irene later moved to Tarzana in California, while Michelle’s father Michael lives in an apartment in Brooklyn.

Trachtenberg’s former co-star O’Donnell, 62, released a statement to People describing the death as ‘heartbreaking’.

‘I loved her very much. She struggled the last few years. I wish I could have helped,’ O’Donnell said.