Ben chatted with Jimmy Kimmel the following night and joked that his younger brother had forgotten to thank him. "I was a little taken aback," Ben confessed on Jimmy Kimmel Live!. "I wouldn't do that. If it's me, I thank people."
"I was sort of just curious as to what I was supposed to be thanking him for," he admitted. "Maybe he thought he was involved in the movie, but he wasn't. There's a lot of things to thank Ben for, but standing at the Golden Globes was not the moment to do it since he wasn't involved in the movie."
As for the SAG Awards Sunday night, Casey saw another nod for Best Male Actor in a Motion Picture, but he revealed he hadn't prepared a speech ahead of time.
"I just try to thank as many people as I can because it seems appropriate and conventional and the right thing to do because there's so many people involved in a movie, until they play the music and someone kicks me off-stage."
Though Casey has been nominated across the awards season board, he admitted he wasn't sure what to expect from the film.
"When I first read the script, I knew it was a very special script, and then, once they asked me to be involved, I wasn't sure it would turn out to be a very special film," he dished. "Over the course of shooting the movie, you never know if something's going to be good or not."
He continued, "I think the hardest part was really just trying to do service to the script because it was so layered and so complex and so perfectly written that you just felt like, if you can not mess it up, you'll be serving the movie in the right way. It was a very heavy move and also a very funny movie and you want to be able to pull both off."
For complete SAG Awards coverage, watch E! News Monday, Jan. 30, at 7 p.m. and 11 p.m. And don't miss the Fashion Police 2017 SAG Awards special Monday, Jan. 30 at 8 p.m., only on E!