'Cher' Crashes Sean Hayes' Guest-Hosting for Ellen DeGeneres

Sean Hayes was having a great time celebrating his 20th time appearing on "The Ellen DeGeneres Show," and he even got to do it as the guest host standing in for Ellen. And yet, something kept nagging at him.

After making his way to Ellen's-- make that his chair, he reminisced about the last time he was on the show as a guest and Brad Pitt was just randomly in the audience and wondered if there were any celebrities in his audience.

As the camera panned along, he pondered and looked closely and as it hit the aisle seat, there was "Cher" in all her decadent glory with an enormous headpiece and one of her classic looks. "Nope, no celebrity," he ultimately declared, as the camera stayed right on her, deadpan.

What made it work so well, though, was how the audience began to react as Sean tried to carry on with the show, cracking a joke about the elaborate chair he put in the audience in his own honor as a frequent guest.

The camera kept cutting to audience members trying politely to follow Sean's banter, all the while craning their necks to see if that really is her in the audience.

It wasn't ... but she sure looked like her. More on that in a second.

Later, Sean interrupted himself to address her directly, but kept up the bit. "Do I know you?" he asked, to which she shrugged noncommittally.

"Like if only I could turn back time and remember where I know you from? It's driving me crazy," Sean said, as his guest shrugged and smiled. "Anyway, as soon as I figure it out, I'm going to 'Cher' it with all of you." He even tacked on a quick "I got you, babe" to really lay the puns on thick.

When they threw to commercial, "Cher" simply got up and started performing, accompanied horribly by Sean's over-the-top impression of her made famous on "Will & Grace."

While Sean's guest looked exactly like the legendary performer, we're about 99.9% sure it wasn't her -- and was actually "RuPaul's Drag Race: All-Stars" winner Chad Michaels.

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