Bill Hader Gained 25 lbs. Working on ‘Barry’ Final Season: 'How the Hell'd That Happen?'

Bill Hader filled more roles than just actor while working on four seasons of HBO's Barry, growing as a filmmaker in the process. He also learned he "can't eat sweets" as much as he used to and gained 25 lbs.

"To know that I’ve grown as a filmmaker is really rewarding," Hader, 45, told The Hollywood Reporter in an interview before the SAG-AFTRA strike began. "But I also know that I’m 45 and I put on weight way faster than I used to. That’s what I really learned, that I’m suddenly 25 pounds overweight. How the hell’d that happen?"

Hader also learned he could not eat junk food "the way I used to," he told the outlet. 

The former Saturday Night Live star recalled how a costume designer told him he needed to wear "bigger clothes" because of his weight gain.

"I think it was toward the end of the season that the costume designer was like, 'I think you need to wear bigger clothes. You’re wearing a large, and, well...' " Hader recalled with a laugh. "We’ve got to go up a size, or three. Great!"

When Hader told Access Hollywood about his weight gain while making Barry in April, he said he was "stress eating" during filming. 

"I don't train at all. I eat a lot of doughnuts and stress," Hader told the show when asked if he trained for Barry's action scenes. "I put on... between episodes three and four... I put on 25 lbs. from sheer stress eating. None of that is for the character. That is purely a guy during all the episodes and writing everything, and just stress eating like crazy. I'm in the process of trying to lose it."

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

Hader created Barry with Alec Berg and played the title character, a former U.S. Marine who worked as a hitman before he stumbles into an acting class in taught by Henry Winkler's Gene Cousineau. Hader won two Emmys for his performance. The fourth season, which wrapped in May, earned Hader Emmy nominations for acting, directing, writing, and Outstanding Comedy Series.

In an April interview for PEOPLE in 10, Hader said his sporadic, acute fits of anxiety in real life influenced his award-winning performance on the series. "There's definitely been moments in the show where the character has gotten panicked and got a panic attack, and I definitely felt that before," the comedian explained. 

"When I was on Saturday Night Live I would get panic attacks pretty frequently," continued Hader. "You know Barry has a panic attack and you go, 'I know exactly what that feels like.' "

All four seasons of Barry are streaming on Max.