One of the audience-pleasing numbers from the musical, Mame, by Jerry Herman was when the two pros, Angela Lansbury and Beatrice Arthur teamed up (as Mame and her friend Vera) to sing the comically scathing song, "Bosom Buddies."
It remains one of the great shames that when Hollywood made the movie version, Angela Lansbury wasn't cast, and passed over for Lucille Ball. She had her occasional moments and did better than some people thought would be the case, but ultimately it was far too stilted a performance for character who's a free spirit. And Lansbury's stage performance is iconic.
(Bea Arthur, though, did get to recreate her performance as Vera Charles in the film.)
Years later, audiences got to see why, at least for one number. The two women together again recreated the "Bosom Buddies" song on the Tony Awards -- years after they had since each become TV stars in their own rights. The performance comes complete too even with the original choreography -- and a great deal, still, of audience-pleasing charm. There's a great deal of subtlety and comic timing required for the number -- I've seen a number of other actresses team up to perform it, and while it's a fun song, the other version miss the richness.
This is how it's done