Kellie Pickler may not be on country singer turned pop star Taylor Swift's famous squad but they go way back. Kellie once joined Taylor on her Fearless tour. The duo first met while they were on tour with singer Brad Paisley and formed a close friendship in the following days.
It was then that they penned Kellie's hit single Best Days of Your Life. While on tour, they were talking about how a boy had broken Kellie's heart, and less than an hour later, they finished writing the song. In September 2015, Kellie told The Boot, "I had gone through a really bad breakup a while back, so we wrote the song about the relationship that went sour."
She went on to say that Best Days of Your Life was her "kiss-off song", like Picture to Burn was to Taylor.
Best Days of Your Life was released as the second single on Kellie's second studio album, Kellie Pickler, which was released in September 2008. The single peaked at number 9 on the Billboard Hot Country Songs chart and reached number 46 on the Hot 100. It was later certified platinum by the RIAA.
On her friendship with Taylor, Kellie told Fox News' Diana Falzone, "I’m not a part of any squad, per se...Taylor is an incredible songwriter and entertainer and performer and artist so yeah we’ve been blessed to have written together in the past and cross paths with other people and grow and develop into our own artists.”