The star is seen wrapping her legs around an audience member during her 'Femme Fatale' show in Brazil, to which the fan then kisses her leg.
Spears then quickly jumps off the man and carries on with the performance of 'Lace & Leather', which is lifted from 2008's Circus album.
The 'Toxic' star is currently on the South American leg of her world jaunt, where she is due to play the Anhembi Arena in Sao Paulo on November 18.
It was recently reported that Spears added Backstreet Boy Howie Dorough to support her tour.
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Watch the fan kiss Britney Spears's leg below: