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Keith Urban says being involved in this weekend's concert special honoring The Beatles was "a once in a lifetime opportunity." 

The country star tells "Access Hollywood" it wasn't just special to perform on the show, but to be there and see surviving Beatles Paul McCartney and Ringo Starr perform. 

Urban teams up with John Mayer to perform the White Album track "Don't Let Me Down" during the concert. 

Brad Paisley also takes part in the event. says he was paired with hip-hop star Pharrell Williams for a collaborative cover of "Here Comes The Sun."  In addition, The Civil Wars' John Paul White makes an appearance as a presenter.

The show's lengthy lineup also boasts Maroon 5, Ed Sheeran, Stevie Wonder, Katy Perry, and others -- including surviving Beatles Paul McCartney and Ringo Starr, who close the show. 

After playing separate sets they team up on "With A Little Help From My Friends," then lead everyone in a finale of "Hey Jude." 

"The Night That Changed America: A Grammy Tribute To The Beatles," commemorating the 50th anniversary of The Beatles first appearance on "The Ed Sullivan Show," will air on CBS this Sunday at 8:00 p.m. Eastern.

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