The stage itself became its own palatial spectacle and featured a catwalk where fans got used to seeing some of the world’s biggest stars join the 26-year-old singer.
From Justin Timberlake to Nick Jonas and Mick Jagger, these are THE 12 best stars who hit the stage with Taylor – in order of when they appeared.
Hailee Steinfeld, Lily Aldridge, Gigi Hadid and Lena Dunham (who all happen to be featured in the "Bad Blood" music video) joined Taylor on stage in East Rutherford, NJ on July 10.
Nick showed up the night after The Weeknd to sing a duet of “Jealous” with Taylor.
The long-time pals sang “Royals” on July 14 in Washington, D.C.
Taylor became an honorary member of the girl group on Aug. 14 in Santa Clara, CA. She donned a matching glitzy blue costume and sang “Worth It” alongside Ally, Camilla, Dinah, Lauren and Normani.
The daytime talk show host made concert-goers laugh with her sparkly tutu-ensemble as she danced down the catwalk.
Talk about HILARIOUS. The former Friends star sang “Smelly Cat” with the “Wildest Dreams” singer during her final night at Staples Center on Aug. 26.
Who was your favorite surprise guest?! Vote in the comment section or on Twitter by sending @Katie_Krause a tweet with the #ETnow hashtag.
And speaking of 2015 highlights, check out the video below for all the signs Selena Gomez and Justin Bieber could get back together!