Ariana Grande Sings Holiday Classic with 2 Very Unexpected Guests

It's officially the most wonderful time of the year, which means family gatherings, festive meals and, of course, Christmas music are officially back. Whether it's an original holiday bop or a fresh take on a seasonal classic, there's always room for a little extra Christmas cheer. And Ariana Grande just delivered some with help from two very unexpected partners.

Grande, 33, stopped by the Sunday, Nov. 8, episode of The Tonight Show Starring Jimmy Fallon and surprised the audience with a performance of the holiday classic “O Christmas Tree.” But she wasn't singing solo. Joining her were her Focker-in-Law costars, Robert De Niro and Ben Stiller, who proved they weren't afraid to show off their singing voices. De Niro, in particular, caught everyone's attention with an unexpectedly impressive note.

The festive performance also served as a fun promotional moment for the trio ahead of the Nov. 25 theatrical release of Focker-in-Law, the latest installment in the beloved Meet the Parents franchise.

Grande joins the cast as Olivia Jones, the girlfriend of Henry (Skyler Gisondo), the grown-up son of Greg and Pam Focker (Stiller and Teri Polo).

In the new movie, Henry announces that he plans to propose to Olivia, a confident life coach and former FBI hostage negotiator. While Pam and the rest of the family are quick to welcome her, Greg isn't quite as convinced. In fact, he immediately suspects Olivia might not be the right match for his son.

Things get even more interesting when Greg's longtime nemesis, Jack Byrnes (De Niro), takes a liking to Olivia.

With her impressive negotiation skills, Olivia quickly turns the tables on the family, leaving Greg scrambling to stop the relationship. But as he tries to protect his son, Greg may have to face an uncomfortable truth: He's becoming the very kind of overprotective father he once struggled to win over.

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