Josh Duhamel thinks his son looks so much like wife Fergie, he's "not even sure" the little boy is his.
The 'Lost in the Sun' actor thinks it is "really beautiful" that two-year-old Axl bears so much of a resemblance to his mother, even if he can't see any of his own features in the youngster.
He joked: "He definitely looks like my wife. I look at those two together and I'm like, 'Wow! that's amazing! I'm not even sure if this is my son!' "
But the 42-year-old star thinks Axl is already showing signs of personality traits that both his parents have.
He added to ETonline: "As far as his personality, I think he really has both of us [but] It's too early to say.
"He's definitely got a personality, this kid, and it's beautiful."
Meanwhile, Axl is getting very excited for Halloween (31.10.15), but still hasn't finalised his costume.
Josh said: "He knows what Halloween is and he loves watching his Halloween videos. It's not just five little monkeys jumping on the bed, now it's five little zombies jumping on the bed.
"The big question is whether or not he's going to be a construction worker or a Teenage Mutant Ninja Turtle."