Britney Spears thrilled the crowd at her Las Vegas show on Monday night (30Dec13) by performing with former 'N Sync star Lance Bass.
The pop superstar kicked off her residency at the Planet Hollywood Resort and Casino in Sin City on Friday night (27Dec13), and introduced a section of the show during which a male audience member is plucked from the crowd to perform with the star on stage.
Tv host Mario Lopez was the lucky guest during the first concert, and on Monday, Spears was surprised to find her longtime friend Bass had been picked for a turn on stage.
Bass, who worked with Spears' ex-boyfriend Justin Timberlake in 'N Sync, was pictured grinning as the singer serenaded him and she later thanked him in a post on Twitter.com, writing, "Lance Bass So so good to see you!! Thank u (sic) for coming tonight," while the former boyband star added, "Thank you for dressing me up as a kitty and spanking me! It's like old times. Xoxo Love ya (sic)!"
Socialite Paris Hilton was also in the audience with her sister Nicky.