During the fifth and final show of her 1989 World Tour, Taylor Swift sold out every event at Staples Centre, and she was joined on stage by a very special guest.

As she and Taylor, 25, made an incredible appearance, best friend Selena Gomez, 23, drove fans into a frenzy. It was a perfect end to the incredibly successful five-night run.

The pair sang Selena’s song Good For You, which Taylor had declared to be her “favourite thing she’s ever done” back in June.

For their duet, the best friends dressed sexily and wore black heeled boots that reached their thighs.

Taylor wore a pair of white hot pants that were fastened to her boots with braces and a white crop top that showed off some cleavage.

Selena chose a black romper with a plunging neckline and spaghetti straps.

Actress Lisa Kudrow joined the Shake It Off star onstage as well.

The Friends actress surprised everyone by performing a rendition of her sitcom character Phoebe’s song Smelly Cat alongside Taylor, nearly bringing the house down.