Colleen Hoover is taking sides. The author, 45, took to social media to promote Britney Spears' 2023 memoir, The Woman in Me, on Tuesday, October 21, the same day that the pop star's ex-husband Kevin Federline released his own tell-all, You Thought You Knew. "Let's get this baby to number 1!" Hoover wrote via Facebook alongside an Amazon link to Spears' book. In the comments section, fans rallied behind Spears, 43 - and Hoover's campaign.