Brit touched down in Vegas around 9:15 pm PT last night and X17 was there to greet her at the airport!

Britney headed straight to the Palms Hotel & Casino and we're just wondering ... why is she arriving in Vegas the day before Kevin's set to attend a party in his honor at Prive?

As we reported two weeks ago, KFed is getting a Father of the Year award at Prive tonight, two days prior to Father's Day.

WILL BRITNEY AND KEVIN CROSS PATHS??? WILL BRITNEY ATTEND TONIGHT'S PARTY IN HONOR OF HER EX-HUSBAND???