Lady Gaga attended one of Britney Spears' Las Vegas shows and posed with the superstar backstage on Saturday.

"She looked so gorgeous, the show was so much fun, and her dad gave us THE BEST BBQ. It was a #MonsterParty!" Gaga wrote as the caption on the picture she shared on LittleMonsters.com.

The Applause singer wore a short blue dress and sunglasses as she stood next to Spears, who sported one of her outfits from her two-year Piece of Me residency at Planet Hollywood.

Miley Cyrus Attends Britney Spears Las Vegas Residency, Kisses & Grinds On Female Dancers

Before the show, Gaga also posted a photo of herself on Twitter with the caption, "On my way to #BritneyB-tch in #ARTPOPStyle long blond hair, androgynous wear."

Spears was clearly excited by Gaga's appearance and tweeted her a special message: "Come hang before the show starts. Can't wait to see you."

Two two stars are also rumored to be working on a song together. Spears previously expressed her desire to work with Gaga during an online chat with her fans last December.

"I would do a duet with Lady Gaga," the star said. "I think that would be a lot of fun. I think she's very different and interesting and intricate, and I like her as an artist."

And according to an Us Weekly source, "It'll happen soon." The two singers reportedly even spoke about it backstage at the Feb. 1 show.

Tags: Britney Spears Lady Gaga