Finally, we want to tell you about the two sisters who were doing those high kicks side by side for the very first time as Radio City Rockets. Here's Joe Fryer.

For so many of the Radio City Rockets, before they were dancing on the stage, they were watching from the audience, including Jordan and Danielle. Betcher you probably get this a lot, but are you sisters?

We are sisters, yes.

Danielle, the oldest, remembers seeing the Christmas spectacular with her grandpa when she was 13.

And he must have seen that look on my face of just like pure joy, because he leaned in and he goes, you know, someday you could do that if you wanted to.

Ten years ago she did, and seven years ago, her sister did. This year, for the first time, they're right next to each other on the kick line.

I just know that she has my back both on and off stage.

Danelle Morgan also has their backs. She's a swing ready to step in when someone is out.

It's an incredibly challenging job. We don't just learn the one track that a single Rocket will do in the show. We learn the entire show.

Sometimes do you only have like a moment's notice before you have to jump in?

There have been times where it's mid show and then all of a sudden we're on the stage.

An 18 year Rocket vet, she knows her parents could be in that audience.

They pop up and they show up in the front row for a show where I'll hear my dad cheering and I'm like, oh, my gosh, my parents are here. They didn't tell me they're here, but they're here.

Okay, so your parents don't always warn you that they're coming?

Oh, no, they don't always warn me. I can see my mom's glasses reflecting with the lights. And it's just really special to know that there's love coming at me while I'm for me.

Reminder, the Rockets are not just in sync with each other, but with you, too. Joe Fryer, NBC News, New York.

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