The girl group joined the singer on stage at the Santa Clara, California, stop of her 1989 World Tour to perform "Black Magic" in front of a stadium crowd of screaming fans.
Taylor called up the girls, put them on a jet and flew them to the tour spot where they met, performed and brought girl power to a whole new level.
"We met her and genuinely she is one of the loveliest people we have ever met -- so down to earth and just the nicest person ever," Jesy Nelson told us. "And would literally do anything for you."
Literally anything -- even give you a pair of her shoes when you forget them, which is what happened to Perrie Edwards the night of the performance.
"I had no shoes," Perrie recalled. "We thought, 'Oh we would rock up in heels.' Little did I realize I'm like Bambi on ice when I wear heels so I was like 'Oh I need some shoes and she was like, 'Wait a minute,' she went to her wardrobe, brought back a basket full of boots, heels, shoes, everything and was like, 'Is this OK?' And I was thinking, she is so nice. She didn't have to do that. She's just so genuine."
The singers seemed in awe of the "Style" singer, who flew back with them on the jet and had a girly chat, but also offered up some advice.
"You don't realize until you meet her and you're like holy crap how does she stay so on top and so nice and so genuine? She's really, really lovely," Perrie said.
Taylor advice to Little Mix?
"To always stick together as a group," Jesy said. "She said what she loves about us is how much we are such a unit and she loves how there is no one in the group that is like, 'Oh look at me.' She's like I love that you are four and that's how you should stay and that was really nice."