Dia Dipasupil/Getty Images; Gabriel Olsen/WireImage James Marsters (left) and Joss Whedon
Marsters, who played Spike on the hit teen series and its spinoff, Angel, said in a Twitter post on Friday that he was "heartbroken" following allegations that Whedon, 56, had created a "hostile and toxic" work environment on the set of both shows.
Reps for Whedon did not have a comment at this time.
"While I will always be honored to have played the character of Spike, the Buffy set was not without challenges," Marsters, 58, said. "I do not support abuse of any kind, and am heartbroken to learn of the experiences of some of the cast."
The actor added, "I send my love and support to all involved."
While I will always be honored to have played the character of Spike, the Buffy set was not without challenges. I do not support abuse of any kind, and am heartbroken to learn of the experiences of some of the cast. I send my love and support to all involved.
— James Marsters (@JamesMarstersOf) February 12, 2021
Everett Collection James Marsters as Spike
Recently, Charisma Carpenter — who starred as Cordelia Chase on Buffy the Vampire Slayer from 1997–1999 and Angel from 1999-2004 — shared a lengthy statement on social media, accusing Whedon of making repeated threats to fire her and efforts to "alienate" her from her peers.
"For nearly two decades, I have held my tongue and made excuses for certain events that traumatize me to this day," Carpenter, 50, began in her statement. "Joss Whedon abused his power on numerous occasions while working together on the sets of Buffy the Vampire Slayer and Angel. While he found his misconduct amusing, it only served to intensify my performance anxiety, disempower me and alienate me from my peers."
"The disturbing incidents triggered a chronic physical condition from which I still suffer," Carpenter added. "It is with a beating, heavy heard that I say I coped in isolation and, at times, destructively."
John Sciulli/Getty; Jon Kopaloff/FilmMagic Charisma Carpenter (left) and Joss Whedon
During one alleged instance, Carpenter claimed Whedon asked her if she planned to "keep" her baby after learning she was pregnant. She also claimed he "callously" called her "fat" to colleagues during her pregnancy.
"He proceeded to attack my character, mock my religious beliefs, accuse me of sabotaging the show, and then unceremoniously fired me the following season once I gave birth," she claimed.
Following her claims, her Buffy costars Sarah Michelle Gellar, Michelle Trachtenberg, Amber Benson and Eliza Dushku all came forward in support of Carpenter, with Benson noting that the set was a "toxic environment."
Want to get the biggest stories from PEOPLE every weekday? Subscribe to our new podcast, PEOPLE Every Day, to get the essential celebrity, entertainment and human interest news stories Monday through Friday.
Anthony Head, who played Rupert Giles on the show, spoke about the allegations against Whedon during a virtual sit-down with ITV's This Morning and said he was "gutted" by the claims.
"This is not a man saying, 'I didn't see it so it didn't happen,' " he said. "I am gutted. I'm seriously gutted because one of my memories — my fondest memory — was the fact that it was so empowering. Not just with the words in the script, but the family feel of the show."
"I am really sad that if people went through these experiences," Head added.
RELATED VIDEO: Michelle Trachtenberg Says There Was a Rule on Buffy Set That Joss Whedon Could Not Be Alone with Her
The new allegations come the year after actor Ray Fisher accused Whedon of being "gross, abusive, unprofessional, and completely unacceptable" while they worked together on Justice League in 2017.
WarnerMedia launched an internal investigation after Fisher's claims, and said when the investigation concluded in December 2020 that "remedial action has been taken."