Maude Apatow is mourning her late friend and "Euphoria" co-star, Angus Cloud.

The actor died Monday at age 25.

"Angus was the funniest person ever," Apatow wrote in a post shared on Instagram Wednesday. "I would get so excited to see on the schedule that we would be working together because I knew we'd have the best day, laughing so hard."

Cloud played Fezco, a sweet-natured drug dealer who grew a close connection with Apatow's Lexi in the HBO teen drama. (CNN and HBO are both part of Warner Bros. Discovery).

"He was the sweetest and made everyone around him so happy," Apatow's tribute continued. "He was just the best. Words can't really capture how magical of a person he was. My heart is broken."

The cause of Cloud's death has not yet been determined. His family shared he had buried his father days prior to his death in a statement to CNN on Monday.

"The only comfort we have is knowing Angus is now reunited with his dad, who was his best friend. Angus was open about his battle with mental health and we hope that his passing can be a reminder to others that they are not alone and should not fight this on their own in silence," they wrote.

Apatow concluded her post with a message of gratitude for her colleague.

"Angus, getting to know and work with you was one of the greatest joys and blessings of my life," she wrote. "I will love you forever."