Iggy Azalea and Britney Spears took us to space when they debuted "Pretty Girls" at the 2015 Billboard Music Awards tonight (May 17), and it was more than we could handle.

The ladies teamed up for their first live performance together at Britney's home turf, Planet Hollywood, and it was incredible to see the divas duet -- especially with Iggy singing the chorus instead of just rapping throughout the track.

Britney rocked a barely there sheer leather outfit while Iggy went for a silver metallic dress, and they both really went for it with the sexy alien look. As a bonus, their big headset mics reminded us of '90s Brit-Brit, as did their in-sync choreography. (See what we did there?)

It was hard to keep up with everything going on in "Pretty Girls" -- with rollerbladers, light-up jump ropes, disco lights and pyrotechnics making for a fun house-party-in-space vibe.

Dare we say their Billboard performance was even better than their bonkers throwback alien-themed music video?

Watch the killer performance above.