Star Spotting: Rihanna Flips Her Switch In London

Just yesterday we were speculating that Katy Perry's new (somewhat unofficial) song "E.T." owed a sonic debt to Rihanna's Rated R album. Now, here we are with Rihanna showing that influence is a two-way street.

Rihanna, who'll apparently be in Katy Perry's wedding party when she ties the knot with Russell Brand, is seen above rocking a light-up dress at London's O2 Arena. It's not unlike the CuteCircuit gown that Perry wore at the Met Costume Gala.

Who do you think lit it up better? Let us know in the comments. And while you're at it, enjoy Katy's "Waking Up In Vegas" videos, below. And check out Rihanna in another light-up look.