It’s a big day for Elton John fans: his duet with Matthew Morrison from the “Glee”-meister’s  forthcoming solo set got a little leak today, and, more importantly, John released new dates for his return to Las Vegas’s Caesars Palace.

It’s been rumored for some time, but now it’s official: John begins a new residency  at the hotel’s Colosseum Sept. 28 for 16 shows.  The return is the first stint in a new three-year residency. His initial run ended in 2009. Instead of a red piano, this show is dubbed “The Million Dollar Piano.”  Tickets, which go on sale April 25, range from $55 to $250 plus fees.

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Now back to that duet: the two sing a medley of John’s lovely, but relatively obscure,  “Mona Lisas and Madhatters” and the well-known “Rocket Man.” In the below snippet, we don’t get to hear them singing together much, other than on the “Rocket Man” chorus, but it’s pretty much what you’d expect. John switched up “Rocket Man” a little from the original radio version that appeared on 1972’s “Honky Chateau” (“Mona Lisas” is from the same album) and it suits his now-deeper voice. He lets Morrison grab for the high notes.  Morrison has one of those great Broadway voices that can seemingly sing anything, but has no truly distinct quality of its own, at least not here. We’ll reserve full judgment until we can hear the whole song.