At the world premiere of 20th Century Fox’s film “Night at the Museum: Secret of the Tomb” held at New York’s Ziegfeld Theatre on Thursday, the cast honored the life of the late Robin Williams, who makes his final screen performance in director Shawn Levy’s third installment of the popular franchise. Williams’ widow, Susan Schneider, attended the event.

Williams died on Aug. 11 at his home in Tiburon, Calif. He was 63.

“I will never forget his generosity,” Ben Stiller told Variety. “I got to work with him a few times over the years, and he was the kindest person.”

Co-star Ricky Gervais remembers the Oscar winner mostly as a caring friend.

“We quickly became mates. He was so approachable and just a lovely bloke,” Gervais shared. “He made you feel good however he was feeling. I will always remember the time I was doing the Bob Woodruff benefit with the soldiers and Robin stayed by the stage all night watching all the acts. He laughed and told everyone how good they were. He didn’t have to do that. He treated everyone with so much respect. That sums him up. He was so sweet.”

For Skyler Gisondo, who plays Stiller’s son in the family adventure movie, Williams was a mentor and the guy who helped him get a date for the high school prom.

“I was a senior in high school at the time of filming, and I wasn’t going to be back in time to ask a date to the prom,” Gisondo told Variety. “So I asked Robin and Ben to be in a prom proposal video that I was making to ask a girl. I got enthusiastic yeses from both of them. When we were about to shoot the skit, Robin kept asking me, ‘Can I say this? Can I say that? Is it okay if I make a joke?’ And I’m like, ‘You’re Robin Williams, please say anything you want.'” When the cameras started rolling, Robin started marching around and making funny jokes about me. The video worked and she said yes. Making that with him was the highlight of my life.”

Owen Wilson collaborated with Williams on all three “Night at the Museum” films, but it was during his time off the set that he bonded with the comic.

“I was always paired with him at the press junkets, and seeing Robin up close was a huge learning experience,” Wilson said. “The junkets can be a little tedious, and he was always telling fresh, funny jokes. Seeing how brilliant he was made me realize he was one of the best. There will never be anyone like him.”

After the screening, the night’s festivities concluded at the American Museum of Natural History’s Theodore Roosevelt rotunda, which was a fitting tribute to Williams as he plays the 26th president in the film. Many guests brought their children to the bash, including Stiller and his wife Christine Taylor. Partygoers ate chicken fingers, macaroni and cheese, steak and pepperoni pizza.

“Night at the Museum: Secret of the Tomb” opens Dec. 19.