Taylor Swift joined onstage by Julia Roberts and Joan Baez

Taylor Swift's contacts book must be hilarious.
If you've missed it, the 1989 starlet has been bringing big names to join her onstage throughout her American tour - ranging from Ciara and Nico & Vinz to the entire USA Women's football squad.
This time, she flicked towards the letter 'J' in her phone, and found two willing guests to join her at a show in California - Julia Roberts and Joan Baez both hopped on stage Saturday night.

Tonight Joan Baez and Julia Roberts danced it out to 'Style'. These two women are my heroes. What an honor. pic.twitter.com/ERFqo1SS8H

— Taylor Swift (@taylorswift13) August 16, 2015