N'Sync singer Lance Bass indulged in a spot of light bondage with Britney Spears last night (December 30) in Las Vegas.

The pop princess was running through her Piece of Me residency show in Planet Hollywood when friend Bass ended up on stage.

The singer was pictured tied up and being led on all fours by Spears on the stage.

The former X Factor USA judge tweeted Bass post-show, to which he replied:

"Thank you for dressing me up as a kitty and spanking me! It's like old times. Xoxo Love ya."

Spears meanwhile opened her Piece of Me show on December 27, with the singer expected play around one hundred shows over two years.