Madonna adopted Miley Cyrus' signature tongue waggle as she joined the pop star for two songs at her MTV Unplugged show in Los Angeles on Tuesday night (28Jan14).
The two stars performed a mash-up of Miley's We Can't Stop and Madonna's Don't Tell while wearing matching glittery cowgirl outfits.
As Madonna left the stage after her performance, Cyrus, who playfully smacked her guest's bottom, told fans, "That was pretty f**king cool... It sounds super-lame, but as a pop star it's pretty cool performing with Madonna...Today was one of those days that it was really easy to get out of bed."
The 11-song concert featured a cover of Dolly Parton's country hit Jolene, which Cyrus also performed at Clive Davis' pre-Grammys party on Saturday night (25Jan14).
The full show will air on Wednesday (29Jan13).