Lindsay and Ashlee were once friends. They were seen going out to dinner at Koi with Paris Hilton
However, soon after the Lindsay/Wilmer breakup, Ashlee and Wilmer were seen together on the set of one of his movies or something, prompting Lindsay to believe that Ashlee was making a move on her ex-man, so Lindsay spread the rumor around her "young hollywood" clique and Ashlee wrote a song about it.