Paul McCartney was joined by Aerosmith frontman Steven Tyler on Friday night (June 28th) during the first night of his two-show stand at Las Vegas' T-Mobile Arena. Tyler and "Macca" trade off lines during a particularly hot rendition of the Beatles' 1968 "White Album" classic, "Helter Skelter."

Tyler and McCartney have been friends for years, with Tyler having performed selections from Abbey Road during the former-Beatle's 2010 Kennedy Center Honors tribute. Their daughters -- Liv Tyler and Stella McCartney -- have been close for decades.

During his recent solo shows, Tyler has been performing a medley of Beatles tunes featuring "I'm Down," "Oh! Darling," and "Come Together."

Rusty Anderson, who's been Paul McCartney's lead guitarist for the past 18 years, recalled how the band finally got the McCartney to add "Helter Skelter" to his concert setlists: "I was working on Paul for 'Helter Skelter' since the first time we played the Super Bowl, before we even went on tour (in 2002). I said 'Hey, y'know what would be a really rad song to play, Paul?' He said 'what?' I said 'Helter Skelter,' and he goes (imitates McCartney) 'Oh, yeah' (laughs). It took him a while to warm up to it. And we kept prodding him and prodding him and he put it in the set -- but we still hadn't rehearsed it. We said, 'Paul are we gonna rehearse 'Helter Skelter?' And finally we did it. . . and I remember playing it at rehearsal and some of the pre-show dancers started coming out and dancing and rocking to it and all of a sudden he started realizing how great it is."