The highly anticipated "Pretty Girls" dance and rap collaboration between Britney Spears and Australian rapper Iggy Azalea was officially released Monday.

The track was leaked Saturday, but Azalea quickly took to Twitter to tell her nearly 5 million followers, "We would really appreciate everyone holding out until Monday to share links etc if possible (i know its hard, I'm excited too!)."

Azalea also hinted as to what fans could expect from the track: "Also for the record brit and i are both singing the chorus's together... i guess you guys aren't used to hearing my singing voice :-)"

When the song officially released Monday at midnight, Spears tweeted, "Thank you all for the amazing feedback on #PrettyGirls!! Going to bed now with a smile on my face. Have some more surprises coming soon!"

Los Angeles fans of the pop star and Australian rapper were given the opportunity to listen to the single before it hit the airwaves by ordering an Uber ride, reports the Verge. Between 3 to 9 p.m. PST on Sunday, the taxi cab app had branded Britney Spears SUVs available for rides with "Pretty Girls" blasting out on repeat.

"Enter promo code PRETTYGIRLS in the Promotions section of your app to unlock the Britney vehicle option," Uber wrote on its company blog. "Limited Britney SUVs may include surprise gifts, and 5 lucky requesters will win 2 tickets to her concert in Las Vegas and a meet and greet with the icon herself."

Fans who caught a ride in one of the "limited availability" vehicles fulfilled their end of the bargain by posting pictures on social media using the appropriate hashtags.

Huffington Post reports the pop star and the "Beg For It" rapper will team up to perform "Pretty Girls" at the Billboard Music Awards on May 17. The pair are also releasing an 80s-inspired music video for the song.

Spears has teased on social media that there are "more surprises" to come.