Sources close to the band tell us Steven Tyler, Joe Perry and co. are taking the stage Monday night at Radio City Music Hall in NYC to close out MTV's award show. We're told they're going to be performing their smash hit "Walk This Way."

We got the band out in NYC Monday ... and each member seemed to drop hints at a possible collab for their performance.

Considering the size of the venue, it'll be the perfect warm-up for Aerosmith ... the band's got a Vegas residency coming up. As we reported ... the band announced they'll be hitting the strip next Spring and putting on 18 shows at the MGM Grand Park Theater ... which seats 5,200 people.

RCMH seats more people -- a skosh over 6,000 -- but is significantly smaller in square footage. All in all ... we're guessing it'll be good practice for the Boys from Boston on a smaller stage than what they're normally used to. Might as well get it in early and often.

Also noteworthy ... Aerosmith had a pretty epic opening performance at the VMAs in 1999, where they also played "Walk This Way" ... but had some help from Kid Rock and Run-D.M.C.