137925960DT012_1_OAK_Las_Ve.JPGDenise Truscello/WireImage

She's still rocking hair the color of Smurfette's skin, but it doesn't look like newly single Katy Perry is singing the blues!

Last night the pop star co-hosted the GiveLove charity event with J. Molinari Jewelry designers Markus Molinari and Jason Arasheben at the grand opening of 1 OAK Las Vegas at The Mirage, and she looked absolutely amazing on the red carpet. The "The One That Got Away" singer been laying low since the news broke in late December that she was splitting from husband Russell Brand, so it's good to see her back out and about.

Katy and Marcus presented a check for $50,000 to GiveLove's co-founders, Patricia Arquette and Rosetta Getty, and other guests at the bash included Paris and Nicky Hilton, Scott Disick, Chris Evans, David Arquette, Christina Milian and Shenae Grimes. Sounds like a blast!