"Pretty Woman" actress Julia Roberts hit the catwalk during Taylor Swift's 1989 World Tour concert stop on August 15 at Levi's Stadium in California. 

Taylor Swift has been inviting many of her celebrity friends to join her on a fashion runway during her performance of the hit song "Style". She has again surprised her fans during last Saturday's show when she was joined by not only Julia Roberts, but also with singer Joan Baez. 

Roberts, 47 and Baez, 78, who were both wearing Taylor Swift's tour T-shirts, linked arms with the 'Bad Blood' singer as they walked and danced to the beat on the catwalk. 

"Please welcome to the stage, the legendary singer-songwriter Joan Baez and the academy-award winner, Julia Roberts," the 25-year old pop star said as she introduced them to the crowd.

Taylor Swift shared on Twitter, "Tonight Joan Baez and Julia Roberts danced it out to 'Style'. These two women are my heroes. What an honor,"

The pair were not the only the surprise guests invited for the evening as she also brought the British band 'Little Mix' on stage to perform their hit single "Black Magic".

On her Instagram page, Swift posted a groupfie with the girl band and she captioned it, "Little Mix smashed it in front of 50,000 screaming fans tonight #1989tourSantaClara".

Among Swift's celebrity pals who already appeared on her sold-out 1989 world tour shows included Kendall Jenner, Cara Delevigne, Serena Williams, Gigi Hadid, Ciara, Lena Dunham, Nick Jonas, Uzo Aduba and Mariska Hargitay.

Julia Roberts on the other hand, will be releasing her new movie "The Secret In The Eyes" in theaters on November 20. The actress is also working on her upcoming American drama thriller film "Money Monsters" which will be initially released in March next year.

Taylor Swift will be performing next at the Gila River Arena in Glendale, Arizona Tuesday, August 18.