"Addiction" is a song written, produced, and performed by American singer and record producer Ryan Leslie. It features vocals by American singer Cassie and American rapper Fabolous, who wrote his guest rap verse. The song contains elements from the composition "I Can't Help It" written by Stevie Wonder and Susaye Greene, as performed by Michael Jackson. Released as the second single from his self-titled debut album, Ryan Leslie (2009), it was sent to rhythmic and urban contemporary radio stations in the United States on July 7, 2008. The track was made available for digital download the following day through Universal Motown Records and Leslie's NextSelection imprint. A version of the song featuring just Cassie was also included in physical versions of the single.