See Josh Duhamel's adorable photo of son Axl Jack wishing mom Fergie a happy 39th birthday on Thursday, March 27. Credit: Courtesy Josh Duhamel; Inset: Jason LaVeris/FilmMagic

He says happy birthday, mommy! Josh Duhamel posted an adorable Instagram photo of his nearly 7-month-old son, Axl Jack, wishing his famous mom, Fergie, a happy 39th birthday on Thursday, March 27.

In the sweet snapshot, Duhamel holds his wide-eyed baby son on his lap -- and holds up a sign that reads, "Happy Birthday Mommy!!!" Axl stares into the camera, mesmerized, as both his hands are held open, like he's anticipating a hug.

The tot will celebrate 7 months on Saturday, March 29 -- and he's starting to resemble his pretty momma slightly more! Last November, Ellen DeGeneres was convinced baby Axl looked just like his dad, which Fergie affirmed during on the show. "[Josh has] got a little mini me," the first-time mom gushed.

The Black Eyed Peas singer told DeGeneres that unlike his dad, Axl has rocker roots -- like his mom. "I had this dream and I was in the audience at this festival," she shared. "On stage singing was Jim Morrison and then came Bob Marley and then Axl Rose. I was in heaven in this dream and I'm dancing and just getting into the music."

Fergie said her heavenly reverie was disturbed by her son, kicking for the first time within her womb. "It was really beautiful," she said. "I woke Josh up and I said, 'honey, honey, honey! he kicked me. He finally kicked me.'"