Dr. Seuss's story How the Grinch Stole Christmas has been stealing hearts for decades. A musical production at Madison Square Garden is faithful to the script — except for a character you may not expect in Whoville.  NY1's Stephanie Simon steps in for a cameo. Here's her account:

(Dr. Seuss's "How the Grinch Stole Christmas" at Madison Square Garden).

Usually you have to wait until the end of How the Grinch Stole Christmas to get that warm, fuzzy feeling, but for me it starts the moment I arrive at the theater. I'm doing a small cameo.

(Gavin Lee, fresh off his role as Squidward in "SpongeBob SquarePants: The Broadway Musical," takes center stage as the Grinch in "How the Grinch Stole Christmas" at Madison Square Garden.)

"Like last week, I got a terrible cold and Andrew, who's one of the Who's but my understudy, was suddenly on," Lee told me. "It's very nerve-wracking, but at the end of the show you always feel so amazing because you got through and you kind of saved the show. So you're going to save the show tonight because you're stepping in."

And don't you know it, as we got ready for rehearsal, we ran into Andrew Boetcher, who gave me this advice: "Just go with the flow and enjoy being at Who in Whoville and we'll take good care of you on stage."

I don't have much professional experience. In kindergarten, I did play a plant in Peter Rabbit. So I rely on Lilly Tobin, who plays Bugsy Who. She holds my hand and pulls me the through the rehearsal. I'm playing Cherry Who with an awesome cream puff hat with a cherry on top.

(NY1's Stephanie Simon, left, rehearses for her role as Cherry Who).

I'm feeling good until Stage Manager Richard Nelson tells me they've added me into a second scene. Oh boy!

Spoiler alert: The Grinch's heart eventually grows three sizes, and I nail my scenes. Seeing The Grinch is like enjoying a holiday confection. Being in The Grinch is the cherry on top!