Sarah Michelle Gellar paid tribute to her “Buffy the Vampire Slayer” co-star Michelle Trachtenberg after she died at the age of 39.

“‘Michelle, listen to me. Listen. I love you. I will always love you. The hardest thing in this world, is to live in it. I will be brave. I will live… for you.’ 💔💔💔🗝️the actress wrote via Instagram Thursday.

The statement, notably, is loosely quoted from the “Buffy the Vampire Slayer” Season 5 finale, with Gellar addressing Trachtenberg instead of her character, Dawn.

In the 2001 scene, Gellar’s character, Buffy Summers, sacrificed herself to save her younger sister.

The social media upload included stills from the show, red carpet snaps and a sweet shot of Trachtenberg holding one of Gellar’s babies.

Trachtenberg joined the cast of “Buffy the Vampire Slayer” during its fifth season in 2000.

Gellar and Trachtenberg were longtime friends who knew each other from their days on “All My Children” together.

Trachtenberg was pronounced dead after she was found unresponsive in her New York City apartment on Wednesday morning.

The Post confirmed that the “Ice Princess” star went into cardiac arrest before passing.

The actress’ official cause of death has yet to be revealed, but we’re told she recently underwent a liver transplant.

According to our sources, Trachtenberg’s body is believed to have rejected the transplant.

Additionally, insiders told People that the Disney alum had been dealing with “health issues” and was “really down emotionally.”

“She told friends she was struggling,” the source claimed. “She was really, really sick and open with those in her circle about how much she was struggling.”

One of Trachtenberg’s neighbors, meanwhile, told Us Weekly that she looked “less and less like herself in the last few months.”

Last year, Trachtenberg’s fans admitted they were worried about her health, saying she looked frail and “sick” in the comments section of a selfie shared on Instagram in January 2024.

“Explain to me how I look sick,” Trachtenberg wrote in response. “Did you lose a calendar and not realize I’m not 14. I’m 38. How sad for you to leave such a comment.”

The next day, she shared another selfie and denied allegations that she went under the knife.

“I’ve received several comments recently about my appearance. I have never had plastic surgery I am happy and healthy,” she captioned the picture. “Check yourself haters.”

Several actors, including Blake Lively and Ed Westwick, have mourned Trachtenberg following her death.