Calling all pretty girls. Britney Spears and Iggy Azalea took a trip to Pretty World at Sunday’s Billboard Music Awards. Dressed as alien babes, the blonde duo performed its new single “Pretty Girls” during a pre-taped segment. Brit, who is in the midst of her Las Vegas residency, commanded the stage with her killer choreography, and Iggy got in on the fun too. Watch them bring their blonde ambition to the BBMAs.