Music's biggest stars gathered for the Sinatra 100 special that aired Sunday on CBS - here are some of the highlights from the two-hour show.

Sinatra 100: An All-Star GRAMMY Celebration ran last night on CBS, an event that honored Frank Sinatra himself, who would have turned 100 this year.

Singers like John Legend, Harry Connick Jr., Tony Bennett, Celine Dion, Nick Jonas, Usher, Carrie Underwood and more took the stage to sing some of Sinatra's most famous tunes.

Let's break down some of the highlights from Sinatra 100 in case you missed it, or want to relive the performances.

Adam Levine serenaded the crowd with his rendition of "The Best Is Yet to Come", trying to emulate Sinatra's signature swagger and style. No signature Levine falsetto or high notes to be found!

Underwood, Seth MacFarlane and Zac Brown came together for an interesting performance. Underwood kicked things off with her cover of "Fly Me to the Moon" followed by MacFarlane crooning "Bewitched, Bothered and Bewildered" then Brown sang "Stars Fell on Alabama". Underwood and MacFarlane joined in with Brown at the end.

Alicia Keys took the stage to sing "I've Got a Crush on You". The R&B/pop star showed off her piano skills and amazing pipes in the emotional performance.

The night ended in rousing fashion. Lady Gaga took the stage dressed as Sinatra himself, singing her rendition of "Theme from New York, New York". It was a showstopping way to end the night as Gaga belted the song in a wonderfully over-the-top fashion.

Tags: Sinatra 100 Frank Sinatra Lady Gaga Adam Levine Seth MacFarlane Zac Brown Carrie Underwood