Michelle Trachtenberg’s Buffy The Vampire Slayer co-stars have paid tribute to their “little sister” following her death at the age of 39.
The American actress, also known for her role in Gossip Girl, was confirmed dead after emergency medical services arrived at One Columbus Place, New York, following a call at about 8am on Wednesday, the city’s police department said.
Her death is not being treated as suspicious and the police said the medical examiner will determine the cause of her death.
Emma Caulfield, who played Anya Jenkins on the hit supernatural drama, said the cast had “lost a little sister” in a post shared to her Instagram story where she referred to Trachtenberg as “Mish Mish”.
She wrote: “I’m so sorry your bright light died so young. Our Buffy family lost a little sister today.
“Rest in peace lovely Mish Mish. You were loved.”
How I Met Your Mother actress Alyson Hannigan, who played Willow Rosenberg, shared a series of photos of Trachtenberg including old pictures from when they shared scenes.
She said: “I am deeply saddened by the news of Michelle’s passing.
“She brought a loving energy to the set of Buffy. My thoughts are with Michelle’s family and friends.”
Another co-star, actor David Boreanaz, posted a black and white picture of Trachtenberg to his Instagram story and wrote “So very sad. Horrible news.”
Trachtenberg joined the hit show in its fifth season as Dawn, the younger sister of Buffy, who was romantically linked to Angel, portrayed by Boreanaz.
Elsewhere, James Marsters, who played British vampire Spike, said Trachtenberg was “a beautiful soul” as he shared a selfie of the two together on Instagram.
“My heart is heavy today. We have lost a beautiful soul”, he said.
“Michelle was fiercely intelligent, howlingly funny, and a very talented person. She died much too young and leaves behind scores of people who knew and loved her.
Michelle Trachtenberg, left, messing about on set with Buffy The Vampire Slayer creator Joss Whedon (Damian Dovarganes/AP)
“My heart goes out to her family who are good people and are suffering the greatest loss anyone could bear.
“I hope everyone can give them space to heal in this most difficult time. Godspeed Michelle. You are missed.”
It comes after Buffy actress Sarah Michelle Gellar announced in a social media post earlier in the month that she is “on the path” to reviving the show, alongside a team of “four unbelievably talented women”.
Trachtenberg’s Gossip Girl co-star, Ed Westwick, who played Chuck Bass on the show, said he was “sending prayers” in a post to his social media, featuring a picture of her as Georgina Sparks.
Trachtenberg played a young socialite of Manhattan’s Upper East Side who created havoc throughout the show, blackmailing Serena van der Woodsen (Blake Lively), among other schemes.
Born on October 11 1985 in New York, Trachtenberg began her acting career at the age of three, appearing in adverts before landing roles on TV.
Gossip Girl cast members Michelle Trachtenberg and Blake Lively (Evan Agostini/AP)
In 1992, she secured a recurring role in children’s sitcom, The Adventures Of Pete & Pete, and in 1996 she starred in the film, Harriet The Spy as an 11-year-old given to spying on neighbours and classmates, and concocting outrageous lies to embellish the everyday details in her private journal.
She was also known for playing Penny in the 1999 spy film, Inspector Gadget, and Jenny in 2004 movie, EuroTrip.
In 2005, she starred opposite Sex And The City actress Kim Cattrall in Ice Princess and was also in the 2009 teen comedy, 17 Again, alongside Zac Efron.
More recently, Trachtenberg reprised her role in the second series of the Gossip Girl sequel.
The actress, who was born in Manhattan and grew up in Brooklyn, told the XOXO podcast with Jessica Szohr she knew a lot of people from the Upper East Side, in her 20s, who were “very similar to the Gossip Girl characters and involved in that world”, adding “and some were actually more scandalous than the show portrayed”.