He told E! News: "I mean, women just sort of turn into like animals in this sort of stage that they're in.
"She's a complete animal right now! You can ask her, but in the most beautiful like humanistic animal-y way.
You know she works out all of the time, eats right, impeccably right. She's just a machine."
Channing, 32, also revealed he is terrified but excited about the impending birth.
He added: "I mean, I don't think there's one thing that doesn't terrify you, but in the most unbelievably beautiful way. Someone said it's really like watching your heart jump out of your body and run around, and I think that can possibly be the coolest thing that I've heard of."
Meanwhile, Jenna revealed she has been having strange dreams about floating on a magic carpet since getting pregnant, and thinks her elevated hormones are to blame.
In a Twitter post, she explained: "OK my fellow preggars ladies about these hormonal dreams ... Is it normal to fly on a magic carpet while presenting at Golden globes?? Lol. (sic)"
The 32-year-old screen beauty her 'Magic Mike' star spouse on the set of 2006 film 'Step Up' and married him in 2009.