Katy Perry is known for her love of different costumes, so she is likely to have been in her element when she got to wear fun fancy dress on Sesame Street.
The California Gurls singer has made an appearance on the popular kids' TV show with little red character Elmo, whom she asked to take part in a dressing up game.
Although Katy got into a bride fancy dress outfit - to reflect her impending wedding to Russell Brand - Elmo was less keen to join in.
So the pop star chased him down Sesame Street, resulting in a rendition of her hit Hot N' Cold.
Perhaps she should have worn a ladies' Elmo outfit to help the character bond with her a little better! The episode will air in the US in December, so keep your eyes peeled for clips.
Katy recently dressed up in a variety of costumes, including a cheerleader's outfit, when she was master of ceremonies at an awards show.