"I Belong to You (Il Ritmo della Passione)" (English: "I Belong to You (The Rhythm of Passion)") is a duet by Italian singer Eros Ramazzotti and American singer Anastacia, released as the second single from Ramazzotti's eleventh studio album, Calma apparente (2005), and the third from Anastacia's first greatest hits album, Pieces of a Dream (2005).

It was met with commercial success in mainland Europe, particularly Germany, peaking at number one and becoming the ninth-biggest-selling song of 2006.

The song is a ballad in which Anastacia sings in English and Ramazzotti in Italian or Spanish.

While reviewing Anastacia's Pieces of a Dream compilation, Lisa Haines of BBC Music referred to the song as "a gorgeous duet with Eros Ramazzotti which reveals a silkier side to the hard edge normally so distinctive in her voice, and ends with the kind of lung excess that would put Celine Dion to shame.

"[1] The music video was directed by Don Allan[2] and was filmed in Rome, Italy, on 21–22 November 2005.