She wrote, "Out of Myself, Britney, and Christina - didn't everyone think I was gonna be the troublemaker? LOOK MA!!! No CUFFS!!!"
Britney Spears has never been arrested but has had her run-ins with police.
In 2008, she lost custody of her two young sons after refusing to hand them over to ex-husband Kevin Federline at the end of an agreed visitation. She was hospitalised twice in a month and her father was handed control of her personal and financial affairs. The conservatorship still stands.
Meanwhile, Christina Aguilera is still trying to revive her flagging career following a flop album, Bionic, in 2010 and a poorly-received movie debut in Burlesque.
Late last year (10), she split from her husband Jordan Bratman and was ridiculed twice last month (Feb11) for messing up the lyrics to the National Anthem at the Super Bowl and then stumbling onstage during a tribute to Aretha Franklin at the Grammy Awards.