Platten tells Billboard that the most emotional moment of the evening came immediately before she joined Swift onstage midway through the 1989 performance. "One thing I remember was when the bench was rising -- I was down there [in the rafters], and I was listening to Taylor introduce the song, and I was probably about to lose it for half a second," she recalls. "When the bench rose up and I saw all the twinkling lights and Taylor, I just got so calm and centered. It was exactly how it hoped it would be."
"Fight Song," Platten's self-empowerment sing-along with a chorus that recalls Kelly Clarkson's most chest-thumping anthems, has been slowly infiltrating pop radio after originally being released last June to a muted industry reaction. The song reaches a new peak at No. 25 on the current Hot 100 chart -- and it may rise even higher, now that Platten has Swift in her corner. Prior to Saturday's performance in Philadelphia, Swift posted an Instagram video of herself singing the "Fight Song" hook next to Platten, and the short clip has over 1 million likes on the platform.
The Instagram video was recorded in Pittsburgh, where Swift performed at Heinz Field on June 6. Platten was in the city that day performing at a radio station in the afternoon, and her manager worked with Swift's manager to make the backstage meet-up happen following the 1989 tour performance.
"She radiates love and kindness," Platten says of Swift. "We gave each other a huge hug. I wasn't sure she would know -- I was like, 'Really? You know who I am?' She was like 'Of course! I love your song!'"
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Swift has made her love of "Fight Song" no secret, and Platten now has the ear of one of pop's biggest superstar after toiling in obscurity for the first 12 years of her career. After releasing her first independent album in 2003, the Massachusetts native spent years scrapping for gigs, grinding out small tours and trying to figure out how to make a dent in the music industry.
"I've been trying to do this for a long time, and I got rejected a lot," Platten says. "I had some successes as well, but it didn't really feel like I had a chance anymore. … I wrote 'Fight Song' at a real low moment of feeling like, 'Should I quit? Maybe I was wrong. Maybe I was deluding myself.' There weren't a lot of signs to keep going. But something in me -- this tiny little crazy voice -- would not let me quit. That song was the apex of that moment where it was like, 'You are not quitting. If nobody else believes in you, you have to believe in yourself.'"
"Fight Song" started to slowly find a following on YouTube, and a Pretty Little Liars synch helped the song reach a wider audience as it started taking off at radio (the song has peaked at No. 10 on the Adult Pop Songs chart). The single led the four-song Fight Song EP, which was released last month on Columbia Records and precedes a major-label debut album.
"I feel like I have some stuff that matches 'Fight Song,' not in necessarily the message exactly but in the emotion and honesty," says Platten of her upcoming material. The singer-songwriter has been working with producer Jon Levine and estimates that she's penned 150 songs for her upcoming album, which will "definitely" be out before the end of 2015.
Until then, Platten will continue enjoying the "Fight Song" ride and keeping in touch with Swift, who met up with the rising pop artist after the conclusion of Saturday night's show. "We just had a humongous hug," says Platten. "I was crying, of course -- I can't seem to stop crying tears of joy lately."