Katy Perry Set for First Big Night Out in U.S. Since Split

Credit: John Shearer/AMA2011/Getty

Katy Perry is ready to party again -- for a good cause.

The newly single star will make her first official post-split appearance since calling it quits with Russell Brand Friday in Las Vegas.

Joining her pal Markus Molinari of J. Molinari Jewelers, Perry, 27, will celebrate the grand opening of 1 OAK Las Vegas at The Mirage Hotel at a bash that will double as a benefit for the GiveLove charity.

GiveLove cofounders Patricia Arquette and Rosanna Getty will also join in the party that will feature a performance by Ferras.

Her Friday outing will come less than one month after Brand, 36, filed for divorce December 30.

The "Teenage Dream" singer was originally scheduled to appear at the 2012 People's Choice Awards on January 11, but backed out due for unknown reasons.

Though Perry's pals say she was blindsided and devastated by her husband of 14 months' filing, the singer continues to put on a brave face for her fans.

"I am so grateful for the love and support from people around the world," Perry tweeted at the time. "You guys have made my heart happy again."