Sean Sasser, an AIDS activist and castmember on MTV’s The Real World has died. He was 44-years-old.

Sasser’s death was announced by his friend and co-star, Judd Winick, on Twitter. “Our friend Sean Sasser has died,” he wrote late Tuesday. “Our love goes out to his family & husband Michael. We will miss u so much.” He added a collage of photos of Sasser.

According to MTV News, Sasser was introduced during the third season of Real World with his partner, Pedro Zamora, who revealed that he was diagnosed with AIDS. Zamora and Sasser made history when their commitment ceremony was aired that season, long before gay marriage was legal anywhere in the U.S. Zamora died in November 1994, just hours after the season finale aired.

His life partner Michael Kaplan told Queerty that Sasser died of mesothelioma, a cancer of the lung. While mesothelioma has been linked to people with weak immune systems due to AIDS, no further details on Sasser’s health were revealed.

People notes that in May, Sasser was interviewed by the Washington Blade, sicne he was working as a pastry chef at a Washington restaurant.