Songfacts®:

• Jessica Simpson's "I Think I'm In Love With You" is that pop song that shamelessly samples the 1982 John Mellencamp hit "Jack & Diane." The first 20 seconds of both songs are nearly identical - the only way to tell them apart is by listening for Simpson's vocalizations.
  
  Mellencamp is very picky about how his songs are used in media, but he signed off on this sample. It's the only charting song we know of that samples one of his tunes.
• The song is from Jessica Simpson's debut album, Sweet Kisses, released in 1999 when she was 19. The first two singles from the album were ballads: "I Wanna Love You Forever," followed by "Where You Are," a duet with her future ex-husband Nick Lachey. "I Think I'm In Love With You" was her third single, introducing an upbeat, danceable song into her repertoire. Simpson wasn't on the level of Britney Spears or Christina Aguilera, but she was signed to a major label (Columbia), and even a small piece of the teen-pop pie was a healthy serving in 1999, when the stars were racking up eye-popping sales figures. The Sweet Kisses album sold an impressive 2 million copies. This was when album sales in general were at a peak, before the internet cut into the pie.
• The song was produced by Cory Rooney and Dan Shea, who are also the credited writers along with John Mellencamp. Those two crafted a lot of hit songs of the era for artists like Jennifer Lopez, Ricky Martin and Mary J. Blige.
  
  The Sweet Kisses album has different writers and producers on every track, and Simpson had no real connection with the songs, as she later explained. The songwriters and producers were simply doing their jobs, trying to craft a hit for the latest young pop star. This meant getting into the mindset of a teenage girl, resulting in this song about a girl who thinks her crush is turning into something more.
• Jessica Simpson had a very wholesome image at the time, which is reflected in the music video, where she's romping around an amusement park with her friends. Her younger sister Ashlee is in it, going on rides with Jessica and participating in the group dance scenes. Ashlee became a pop star a few years later with her 2004 debut album Autobiography, which went to #1 in America.
• In 2003, Simpson became one of the first reality TV stars with her own series: Newlyweds: Nick & Jessica. She proved surprisingly watchable as she navigated her new marriage with Nick Lachey, which ended in 2006 a year after the last season aired. She moved into acting and later raised a family with her second husband, ex-NFL player Eric Johnson (they split in 20024), but never gave up on music. By her third album, In This Skin in 2003, she was writing a lot of her own lyrics, and she found that songwriting was a healthy pursuit.