Julia Roberts had admitted that she was full of nerves before joining Taylor Swift on stage last month.

The actress was asked to dance along with the singer at one of her gigs in California in mid-August.

Joan Baez also got in on the action as they hit the stage for the song 'Style'.

Speaking to Extra, Roberts said that she was buckled with nerves before joining Swift.

She said: "It was one of those crazy, out-of-body moments. I can’t tell you anything that happened from the moment I came on stage. I was so nervous."

The actress added that she was at the show with her children, with the cameo coming as a surprise.

When asked if it was planned, mother of three Roberts replied: "No! Oh my God, I would have washed my hair if it had been planned. I was wearing a ponytail, leggings, and tennis shoes."

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Watch Julia Roberts on stage with Swift below: