Billie Eilish honoured Angus Cloud with a touching tribute during her Lollapalooza performance on Thursday night.

During her headlining set at the Chicago festival on Thursday, the 21-year-old singer paid tribute to the Euphoria actor, who passed away at the age of 25 on Monday.

Toward the end of her performance on the T-Mobile Stage at Grant Park, the Bad Guy hitmaker sang her and Labrinth's hit, Never Felt So Alone, which featured in the second season of Euphoria.

"RIP Angus Cloud everybody," the performer announced as she wrapped up the song, leading the audience to erupt into cheers.

The late actor was best known for playing the role of Fezco in the HBO drama series. He acted alongside stars including Zendaya, Maude Apatow, Sydney Sweeney, Jacob Elordi, and more.

Since Angus' death, tributes have flooded in from his fellow stars as well as his fans. The star was also honoured with a nine-foot mural in his hometown of Oakland, California during a vigil that was held on Wednesday night.

The actor's family confirmed his death on Monday, stating, "It is with the heaviest heart that we had to say goodbye to an incredible human today. As an artist, a friend, a brother and a son, Angus was special to all of us in so many ways."

The family added that Angus' death had come shortly after the death of his father, who had battled cancer before his passing.

The cause of the actor's death has not been revealed.