Watch Taylor Swift Bring Out Echosmith for a Second Time on 1989 Tour

Taylor Swift 2015
Kevin Mazur/LP5/WireImage

Taylor Swift performs onstage during The 1989 World Tour Live at MetLife Stadium on July 11, 2015 in East Rutherford, New Jersey. 

Taylor Swift must be a big fan of Echosmith.

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For the latest guest artist on her widely successful 1989 tour, Swift brought out the sibling rock band's lead singer Sydney Sierota to perform their breakthrough hit “Cool Kids.” This marked the second occasion Swift has performed “Cool Kids” with Echosmith in concert. In June, the band joined her on stage in Philadelphia.

“What a great night. We just finished our set opening for @twentyonepilots then raced over to jam w/ @taylorswift13,” Echosmith wrote on Twitter.

Taylor Swift Brings The Band Perry Out for 'If I Die Young' in Indianapolis

Swift shared her personal gratitude, tweeting, “My buddy @sydneysierota was as magical and fantastic as always tonight in Columbus! Love her so much @echosmith.”  

On Sept. 16 in Indianapolis, Swift returned to her not-so-distant country past by bringing out The Band Perry for a sing-along to "If I Die Young.” Country acts Sam Hunt, Little Big Town and Kelsea Ballerini have also made previous appearances on Swift’s 1989 tour stop.