New York, NEW YORK -- The 2015 NBA All-Star Game began with a Nas cameo during Christina Aguilera's opening performance, and when Ariana Grande hit the stage at halftime, she had a little surprise in store, too.

Ariana kicked off her halftime set at Madison Square Garden with "Problem," and looked like she was really there to play cheerleader and perform in her little black-and-white mini skirt and cropped top.

Her backup dancers wore the same color scheme with "NYC" emblazoned on their chest in celebration of this year's All-Star festivities being held in Brooklyn and New York City.

She sang her heart out through "The Way," "Love Me Harder" and "One Last Time," before finally getting to Jessie J's "Bang Bang."

For a minute, it seemed like she would only be performing her vocals on the song, but a few seconds later, screams erupted from the audience when Nicki Minaj emerged in a very fitted black skirt and sparkling bustier top, rapping her verse.

Ariana and Nicki Minaj performing at the 2015 NBA ALL-STAR Halftime show pic.twitter.com/J69MlFPL9D

— fluff (@ArianatorPalace) February 16, 2015

At one point, they met mid-stage, where Nicki Minaj began to grind it out, and Ariana responded by spanking her quickly before the cameras cut away.

These two have clearly gotten pretty comfortable with each after performing "Bang Bang" at awards shows -- including the 2014 Video Music Awards -- and collaborating on Nicki's latest album, The Pinkprint.

After sharing the spotlight for a little, Nicki left the stage and Ariana finished up her halftime performance with "Break Free" to grand applause.

Then they exchanged sweet "thank yous" on Twitter. Apparently everyone involved had a great time.

I love u ARI! thank u!!!! > RT @ArianaGrande: thank u babes!! that was too fun. thanks again NBA & thank u @nickiminaj. i love uu!!”

— NICKI MINAJ (@NICKIMINAJ) February 16, 2015