The unlikely pair were rehearsing on the Hollywood soundstage Monday, with the collaboration due to air on Wednesday night.
MTV commented: “The performance will showcase a more intimate side of Cyrus and feature surprise guests for an unexpected re-invention of the songs that have defined her career, including several from her No. 1 album, Bangerz.
“Miley and her fans have always had an intimate and direct connection through her music, personality and no-holds-barred attitude and the ‘Unplugged’ stage will serve as the perfect platform for her to show viewers what inspires and ignites her music and her passions.”
Cyrus, 21, has compared herself to Madonna in the past and believes they share the same love of controversy and risk-taking.
She recently reflected: “Last night, I was talking about some Madonna performances, and I said, ‘At some point, everything becomes irrelevant.’ Like, no one even thinks about when she did Like a Virgin at the VMAs.
“That just becomes a standard, where it’s just like, ‘Oh, that’s her thing.’ So, I feel like now that I did the VMAs, that just kind of became a standard for me, and then any time I do anything else, they’re like, ‘Miley kept it tame tonight.'”