celebrity Katy Perry clown London Mr. Paparazzi

Looks like Russell Brand's sense of humor is rubbing off on his sexy wife Katy Perry.

While visiting Chris Moyles' Comic Relief fund-raising marathon in London, the curvy songstress couldn't help but put on a bright red clown nose to add a little excitement on Radio 1's Red Nose Day.

Perry was in town for her first show of the London leg of her world tour. The sexy singer went to the radio station at 1:30am ... straight from the concert. What a trooper!

Find out which other celebrities took part in the record-breaking marathon ... after the jump.