In an Instagram video, the musical’s lead, “American Idol” winner Nick Fradiani, introduced Diamond, 84, who delivered an impromptu performance of his hit “Sweet Caroline” from the audience.

Neil Diamond performed "Sweet Caroline" in a surprise appearance on Saturday at his namesake musical, "The Neil Diamond Musical: A Beautiful Noise," in Los Angeles.

Neil Diamond Gives Surprise Performance of 'Sweet Caroline' for “A Beautiful Noise ”Audience The singer retired from concert touring in 2018 after he was diagnosed with Parkinson's disease ...

At the curtain call of the July 12 matinee performance of A Beautiful Noise: The Neil Diamond Musical at the Hollywood Pantages Theatre in Los Angeles, patrons were met with a surprise when Neil ...

Neil Diamond performed "Sweet Caroline" in a surprise appearance on Saturday at his namesake musical, "The Neil Diamond Musical: A Beautiful Noise," in Los Angeles.