Jennifer Garner has revealed she feels like she's been "having an affair" following hubby Ben Affleck's Batman v Superman: Dawn of Justice transformation.

The actress - who has been married to Affleck for nine years - joked during an interview on Live with Kelly and Michael that since Ben has put on 30 pounds of muscle after landing the role of the Cape Crusader, he's like a new man.

[related]Speaking of Affleck's new "ripped" physique, Jennifer said: "You know, he has put on 30 pounds of muscle and he's 8% body fat. He looks pretty good.

"It's a little bit like, 'Whoa, who are you?' It feels like I'm having an affair. But I don't mind, I'm not complaining!"

Affleck previously said about getting into shape for the part: "It's a process that I'll probably have better perspective on when I'm done.

"I can tell you that every time I do a role, it's the responsibility of an actor to get their physical self as close to the role as possible."