The `Firework` singer - who married Russell Brand in India last month - has struck up a close relationship with the funnyman`s mother Barbara and even thinks she would take her side if the couple were to have an argument.
Katy told Now magazine: "Barbara has seen Russell in his darkest days, so she knows better than anyone how much he`s changed.
"He`s a devoted husband but if he steps out of line she and I are really close so she might even take my side."
Katy also revealed her new husband - a keen supporter of London-based soccer team West Ham - wants them to have a huge family.
She explained: "He wants 11 boys named after the West Ham team."
The `Get Him to the Greek` star has previously admitted he doesn`t want his wife and mother to get on too well because he doesn`t want them to gang up on him.
He said: "Katy was lovely when she met my mum. She came round my mum`s house. She`s dead nice and normal, a down-to-earth easy going sort of person. She`s really, really sweet and easy to be around and she was lovely with my mum, they get on well. But you don`t want them getting too much of an alliance going though do you? You want to keep people baffled and confused, you don`t want them coming down on you."