Kendrick Lamar's highly anticipated Super Bowl halftime show just got even more exciting ... 'cause SZA is joining in on the party!

Apple Music -- which sponsors the gig -- dropped the news out of nowhere on Thursday, announcing the 4x Grammy Award winner would be joining K. Dot in NOLA on February 9.

The platform also shared a new teaser for the show, featuring Kendrick on the phone discussing the possibility of adding someone to his set list ... when SZA creeps up behind him and dumps a jug full of blue liquid all over the "Not Like Us" MC.

The partnership makes sense ... not only are they both Top Dawg artists, they also have several songs together -- most recently "luther" and "gloria" on Lamar's "GNX" album.

Performing the SB is a huge deal ... considering the game, year in and year out, draws a massive audience across the world.

Other artists who have gotten the nod in recent years include Usher, The Weeknd, and Lady Gaga ... as well as icons like Michael Jackson and Prince back in the day.

Of course, the choice to go with Lamar was somewhat polarizing, as Lil Wayne -- who's from New Orleans -- thought he deserved the slot.

The whole thing goes down in just 17 days ... get your popcorn ready!