The singer just showed up to Arrowhead Stadium in Kansas City, as Travis and his squad are preparing to host the New Orleans Saints.

Taylor pulled up with her hair in a ponytail ... and she's wearing a plaid off-the-shoulder top and matching mini skirt, with knee-high platform boots and a purse.

Scott Swift, Taylor's father, is with her tonight ... and they were flanked by her own personal security team, plus stadium security guards, as they strutted in and were escorted inside ... likely up to her usual perch from a private suite.

For his part, Travis showed up to work a few hours earlier ... with black sunglasses, a black button down shirt, white shorts and this season's trademark mustache.

Travis also had a canned beverage in one hand and a pair of Jordan 11s in the other on his way into the locker room.

It's the first time we've seen Taylor supporting Travis in person in three weeks ... she missed the last two Chiefs games, which were on the road in Atlanta and then Los Angeles.