"I Think I'm in Love with You" is a song written and produced by Cory Rooney and Dan Shea for Jessica Simpson's 1999 debut album, Sweet Kisses. It contains a sample of singer-songwriter John Mellencamp's "Jack & Diane" (1982) and was released as the album's third and final single in mid-2000; in Japan, it was issued as the album's second single in February 2000. The single reached the top 10 in Australia and Canada and the top 20 in Iceland, New Zealand, and the United Kingdom. In the United States, it peaked at number 21 on the Billboard Hot 100. Los Angeles radio station KBIG-104 produced a mixed version of "I Think I'm in Love with You" with a few samples of "Jack and Diane" lyrics and the same ending as the original version. Simpson recorded a Spanish version of the song titled "Tal vez Es Amor". A radio / single mix of the song was also released with a slightly longer outro. It is 22 seconds longer than the original album version. Composition "I Think I'm in Love with You" is a dance-pop song, with a length of three minutes and 35 seconds. The song samples the signature opening guitar-based melody line of John Mellencamp's 1982 hit Jack & Diane. The song is written in the key of A major, with a chord progression of A–E/A–A–E-D, and the song is set in common time with a tempo of 106 beats per minute. The vocal range spans from D4 to F♯5. Chart performance "I Think I'm in Love with You" was more up-tempo than Simpson's previous singles and became a moderate hit. In the United States, the single entered the charts at #63 on the Billboard Hot 100, on the issue dated July 1, 2000. Due (largely) to the strength of its radio airplay, the song peaked at #21 in its seventh week, and stayed on the chart for 16 additional weeks. The single peaked at #5 on the Billboard Pop Songs chart, and stayed on the chart for 22 weeks. "I Think I'm in Love with You" was her first top-five entry on the chart, and also achieved success on the Adult Contemporary and Rhythmic Top 40 charts. To date, "I Think I'm in Love with You" sold roughly 20,000 physical copies, and has sold over 316,000 paid digital downloads, according to Nielsen SoundScan. In Canada, "I Think I'm