Sia Credit: Theo Wargo/Getty Images

Sia’s got game. To celebrate her 40th birthday, the singer hired drag queens from Bingo Boys Inc. to host a party at a private home December 19, an insider reveals in the new issue of Us Weekly.

Among the competitors: Jennifer Aniston, Justin Theroux, Sandra Bullock and boyfriend Bryan Randall, Jeff Probst and Jason Bateman.

“As we were passing out the bingo cards, I noticed a couple of familiar faces,” Bingo Boys owner Jeffery Bowman later blogged. “[It] was just a nice group of Sia’s friends.”

But the birthday girl — who married filmmaker Erik Anders Lang at her Palm Springs, California, home in August last year — didn’t go easy on her famous pals. Adds the insider, “Sia was very competitive!”

The Australian songstress is no stranger to hanging out with A-listers for big occasions. As Us Weekly previously reported, Sia was one of the few celebs invited to Aniston and Theroux’s hush-hush wedding in August, which was also attended by Bullock and Randall, as well as Howard Stern, Ellen DeGeneres and others.

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