"I Believe in You" is a pop-dance song performed by Australian singer Kylie Minogue and written by Minogue and Scissor Sisters members Jake Shears and Babydaddy. It was produced by Shears and Babydaddy, and received an overall positive reception from music critics when it was released as the first single from Minogue's second greatest hits compilation, Ultimate Kylie, in December 2004. In the upbeat eurodance song, Minogue describes how she believes in her lover rather than anything else.

The single peaked at number two in the United Kingdom and at number six in Australia. The song became a dance club hit in the United States, peaking at number three on the Billboard Hot Dance Club Play chart in 2005 and earning a nomination for a 2006 Grammy Award in the "Best Dance Recording" category.

"I Believe in You (Je crois en toi)" is a duet between Céline Dion and Il Divo, released on May 1 2006. It was the third and last single from Dion's On ne change pas album, and first and only from Il Divo's Ancora.

Luc Plamondon, with whom Dion worked in 1991 on her Dion chante Plamondon album, wrote French lyrics for the song.

"I Believe in You" was released as a radio single in the United States (January 23 2006) and as a commercial single in selected European countries (May 1 2006). It was also issued as a radio single in Canada, in May 2006.

There was no music video made for the song.

Dion and Il Divo pre-recorded performances of "I Believe in You" in various French television shows, in October 2005. They were shown during Christmas 2005.

The single peaked at #30 in France and #35 in Switzerland. It also reached #31 on the U.S. Hot Adult Contemporary Tracks.

"I Believe in You" was featured on the official 2006 FIFA World Cup album, called Voices From The FIFA World Cup, which was released on May 20 2006.

There are two versions of the song, the version released on Dion's On ne change pas album, and the other on Il Divo's album. The only difference is that "Someday I'll find you" is sung by another member of the band.

Il Divo are not first operatic/opera singers who have performed and recorded with Céline Dion. She had previously collaborated with Luciano Pavarotti on "I Hate You Then I Love You" and Andrea Bocelli on "The Prayer." The Prayer has also been performed by Céline and the very successful crossover artist, Josh Groban.