The 61-year-old actor also gushed about John Stamos' engagement -- despite being just hours away from his own proposal!
The Olsen twins will always have their TV dad in their corner!
ET's Deidre Behar caught up with Bob Saget on the red carpet at the Stand Up for Pits benefit in Hollywood on Sunday, where he opened up about Mary-Kate and Ashley's decision not to make an appearance on Fuller House.
"People should do what they want with their lives, and when they're 9 months old and they get a job, [they have a right to stop doing it]," he shared. "I love them very very much, Ashley and Mary-Kate, and they love what they do and acting is not what they want to do."
"People should do what they want to do," he added.
Saget, who announced his engagement to Kelly Rizzo just three days after the event, was in the mood to celebrate another Full House co-star, John Stamos, who proposed to girlfriend Caitlin McHugh last month.
"I love his fiancee, I love Caitlin. I'm happy for both of them. He's my brother, so I have a sister-in-law," he gushed, before commenting on whether Stamos will soon join him in the fatherhood club.
"I got nothing to do with that!" he joked. "When it happens, I'd love to be around. I'll take selfies."
The 61-year-old comedian also opened up about why Sunday's event was so important to him.
"I'm here to help pitbulls, because they are abused and they are hurt and with all that's going on right now in the world, human beings are abused and they are hurt and so my heart is exploding in wanting to entertain and perform and do whatever I can do," he said. "So when Bill Burr called me and said, 'This is such a great cause, Rebecca is a great lady, it's an amazing thing,' I said, 'Just tell me when to be there.'"
See more on the Full House crew in the video below.