Stars are tipping a hat to Paul Reubens.

After a decades-long career, which included portraying the character Pee-Wee Herman, the 70-year-old actor passed away on July 30 following a private battle with cancer.

As news of Reuben's passing emerged on July 31, fans, friends and fellow stars from around the world paid tribute to the late comedian.

"No tweet can capture the magic, generosity, artistry, and devout silliness of Paul Reubens," Conan O'Brien tweeted. "Everyone I know received countless nonsensical memes from Paul on their birthday, and I mean EVERYONE. His surreal comedy and unrelenting kindness were a gift to us all. Damn, this hurts."

Judd Apatow, who worked with Reubens on Pee-Wee's Big Holiday—his final outing as the beloved character—captioned a photo of his collaborator on Instagram with three heart emojis.

Jimmy Kimmel, who had Reubens as a guest on his late-night talk show in Feb. 2020, also honored the late star on social media.

"Paul Reubens was like no one else—a brilliant and original comedian who made kids and their parents laugh at the same time," he tweeted. "He never forgot a birthday and shared his genuine delight for silliness with everyone he met. My family and I will miss him."

See more celebrity tributes to Reubens below.

Natasha Lyonne: "Love you so much, Paul. One in all time. Thank you for my career & your forever friendship all these years & for teaching us what a true original is."

Cher: "Goodbye Paul Goodnight sweet prince May flights of angels sing thee to thy rest."

Paul Feig: "This is devastating. Truly heartbreaking. Paul was such a comedy genius. From his Letterman appearances to his TV shows and movies, he was so original and hilarious. And such a sweet man too. This is a huge loss for comedy. Thanks for all the laughs, Paul."

Dane Cook: "Paul Reubens was a gifted performer and a nice person. He brought so much joy to people over the years as Pee Wee, my sister and I loved that character. I was privileged to work with him in a film and he was as great in real life as he was on screen. Tough news here."

David Hasselhoff: "Paul Reubens was a great, great friend. He gave me the muppets for my birthday and never forgot anyone's birthday from our class. He was in my class at CalArts and we had the same business manager. He was always kind to me and to everyone. He will be missed."

To look back at Reubens' life in pictures, keep scrolling...