Watch Paul McCartney Join The Killers In Surprise New Year's Eve Appearance

"Helter Skelter" was on the set list.

Paul McCartney made an unscheduled appearance on New Year's Eve, joining the Killers on stage in St. Barts for Russian billionaire Roman Abramovich's exclusive New Year's Eve party.

Several attendees caught the moment on video, during which you can hear McCartney sing the Beatles' classic “Helter Skelter.”

Here's a video that appeared on the Killers' Facebook page:

And another from Twitter:

@PaulMcCartney & @thekillers on NYE. I am happy as can be pic.twitter.com/OMiNHqrtIu

— AZ (@Az_Cohen) January 1, 2017

And from YouTube:

McCartney posted a New Year's greeting to fans on his website early on Jan. 1, writing: “Happy New Year’s Day. May this year be a happy and peaceful one for you and your family and everyone around the world. Love Paul.”

On Saturday, the former Beatle announced his first live dates of the year would be in Japan in April.