Britney Spears rang in the new year (14) by taking her boyfriend on stage to perform with her at her final gig of 2013. The Toxic singer kicked off her residency at the Planet Hollywood Resort and Casino in Las Vegas on 27 December (13), and she performed a special gig at the venue on New Year's Eve (31Dec13). During the show, Spears picked her boyfriend, David Lucado, from the audience to take part in a saucy sequence during which her dancers tied him up and the singer led him around the stage on a leash. Pictures show Lucado grinning and laughing as Spears holds him by the leather strap. The pop icon previously acted out the sequence with former 'N Sync star Lance Bass on Monday night (30Dec13).