While speaking to "Extra" on Monday at a red carpet event for ABC's upcoming special, "The Little Mermaid Live!," Stamos teased that his infant son's first words were "trust fund."
“He has a good sense of humor. That’s the milestone I like,” the beaming father said of Billy, whom he shares with wife Caitlin McHugh.
Stamos, 56, went on to reveal that Billy wasn't too thrilled about his dad's role as Chef Louis in the new movie.
“I tried to get him to watch The Little Mermaid, the movie, and he just goes, ‘Coco, Coco, Coco.’ He loves Coco,” said the "Full House" alum. “That’s what he dressed up as for Halloween: Coco.”
Sure enough, on Halloween, Stamos posted an Instagram photo of himself dressed up as Ernesto De La Cruz from the 2017 Disney film while holding his son in his arms.
Although Billy is not the biggest fan of Stamos' role as the chef, it hasn't stopped the tiny tot from distracting his dad during rehearsals.
"I’m rehearsing my number, kinda for the first time on the stage — jumping on these tables, with knives and things — and all I could hear was 'Dada! Daddy! Dada! Dada!'" he said in an interview with Entertainment Tonight during Monday's red carpet event.
"I said, 'Dada’s gonna fall off the table if you don’t shut up, kid,'" Stamos jokingly added with a laugh.
"The Little Mermaid Live!" airs Tuesday at 8 p.m. ET on ABC.