Katy Perry & Russell Brand Rock Out

The singer shows off a new sparkler that looks like an engagement ring when the couple goes out in London

He already got her the Taj Mahal, but now, alleged former ladies' man Russell Brand has reportedly made it official by putting a righteous engagement ring on the finger of his pop-star squeeze, Katy Perry.

Check out the rockage in the accompanying pic! The so-cute-you-could-plotz couple is continuing their unbearable happiness world tour in London.

Cheers!