Angus Cloud and Sydney Sweeney attend the 2021 GQ Men of the Year Party.Photo:Stefanie Keenan/Getty

Angus Cloud and Sydney Sweeney attend the 2021 GQ Men of the Year Party at the West Hollywood EDITION on November 18, 2021 in West Hollywood, California

Stefanie Keenan/Getty

Sydney Sweeneyis honoring herEuphoriacostar and friendAngus Cloudfollowing his unexpected death.

TheEuphoriaactress, 25, shared an emotional tribute to the late actor on herInstagramon Tuesday, calling it the “hardest thing” she’d ever had to post. Clouddied on Mondayat just 25 years old.

“Angus you were an open soul, with the kindest heart, and you filled every room with laughter,” Sweeney wrote. “This is the hardest thing ive ever had to post, and im struggling to find all the words.”

“You will be missed more than you know, but I’m so blessed to have known you in this lifetime, and I’m sure everyone who has ever met you feels the same,” she continued. “This heartache is real and I wish we could’ve had one more hug and 711 run. All my love is with you. 🖤”

To accompany the heartfelt caption, Sweeney shared a carousel featuring pictures of the two of them. She also included a candid shot of the actor smiling, a video of him waving a candle and singing along toJay-Z’s song “Empire State of Mind” and a sweet photo of her, Cloud and their costarMaude Apatowtogether.

The actors starred alongside each other in seasons 1 and 2 of the HBO series. Sweeney played Cassie Howard, a popular girl struggling to cope amidst a messy series of relationships, and Cloud portrayed Fezco “Fez” O’Neill, a drug dealer with a sensitive soul underneath.

Angus Cloud and Sydney Sweeney.Sydney Sweeney/Instagram

Angus Cloud and Sydney Sweeney

Sydney Sweeney/Instagram

In a statement to PEOPLE on Monday,Cloud’s familyconfirmed that he’d died earlier that day in his home in California. As of now, no cause of death has been released.

Sydney Sweeney and Angus Cloud.Sydney Sweeney/Instagram

Sydney Sweeney and Angus Cloud

Cloud’s unexpected death came only a week after his father’s, according to his family. “The only comfort we have is knowing Angus is now reunited with his dad, who was his best friend,” the statement added.

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The family concluded their statement with: “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."

source: people.com