By now fans expect a guest performer or star at every single one of Taylor Swift's shows for her "1989" World Tour. On Aug. 16, film super star Julia Roberts joined Swift and singer Joan Baez on stage during a performance of the song "Style."

According to Billboard, the Oscar-winning actress and the folk singer came out to dance on stage while Swift performed "Style" at the Levi's Stadium in Santa Clara, Calif. The singer shared an image of the two star on Instagram and captioned the photo with, "Tonight Joan Baez and Julia Roberts danced it out to 'Style'. These two women are my heroes. What an honor."

That same night the singer also had British pop group Little Mix take the stage with her to perform their song "Black Magic." Swift shared a picture of her and the group members during their performance in Santa Clara on Instagram.

The previous night Swift brought out Fifth Harmony to take the stage with her, reported ET Online. The singer, who posted pictures on Instagram of the group during rehearsal and then during their live performance, borrowed a blue outfit from the group during a performance of their hit single "Worth It."

"It was amazing! It was honestly -- it was a dream come true," Camila Cabello told ET on the Teen Choice Awards red carpet. "Sixty-five thousand people in the stadium -- and she learned the choreography, wore our tour outfit -- it was seriously a night we'll never forget."

Other stars who have joined Swift on her "1989" World Tour include Nick Jonas, Jason Derulo, Lorde, Andy Grammer, Ciara, Russell Wilson, Fetty Wap, The Weeknd, Nico & Vinz, and models Cara Delevingne, Kendall Jenner, Gigi Hadid, and Martha Hunt.