Watch: Taylor Swift backed up Madonna at the iHeartRadio Music Awards

Taylor Swift knows that pop royalty deserves serious respect, and she offered it up in a major way: For Madonna's performance of “Ghosttown” at the iHeartRadio Music Awards, Swift served as Madge's guitarist and didn't contribute a single vocal.

The duo gave “Ghosttown” a stripped-down acoustic treatment and looked pretty fantastic as they did it. I'd be down for a Swift cover of “Don't Tell Me” soon.