Little Axl's naughty behavior is nothing his famous dad can't handle. Josh Duhamel dropped by The Ellen DeGeneres Show on Tuesday, Oct. 7, to discuss his baby boy's latest milestones, and how wife Fergie has been handling motherhood since giving birth back in August 2013.

"He's walking. He's fully mobile. I just took him to the beach for the first time. I feel a little guilty about that because we live two miles from the beach," Duhamel told DeGeneres.

"I'll take him to the pool with me and we have swimming lessons, but when you have the water rushing up at you it's a little bit different," he continued. "He freaked out a little but he's fine."

Duhamel, 41, and Fergie, 39, celebrated Axl's first birthday with a sports-themed party in August. The birthday boy looked like a rock star while wearing a black skeleton T-shirt and headband, and appeared to be on his best behavior.

"He's also defiant. They get to a certain age and they start to test you a little bit. He'll stick his finger up my nose and I'll say, 'No. Don't do that,'" Duhamel laughed to DeGeneres. "Then he'll stick it up his nose. He thinks it's funny."

Axl's proud parents have been vocal about wanting baby No. 2 since shortly after Axl's birth. Luckily for Fergie, she'll be a lot more experienced when the time comes. Duhamel admitted on the daytime talk show that the Black Eyed Peas singer wasn't on diaper duty that much when Axl first arrived. 

"Well in the beginning it was me, but she's really improved her diaper changing skills in the last year. It's very impressive. She's as good at it as I am now. I had two younger sisters so I had a lot of practice growing up. She had never held a baby before," Duhamel explained. "I don't think she ever really held a baby, especially a brand new one before we had one."