Songfacts®:

• Unlike the Amy Winehouse song of the same name, this "Rehab" is metaphorical. Rihanna has fallen too deeply in love and gotten burned, so now she needs to check into rehab to get over him, as if he's an addiction or a disease.
• This song was written by Justin Timberlake, Timbaland and Hannon Lane. Timbaland also produced the song with Lane and contributed backing vocals with Timberlake on the tune's bridge ("ladies, gimme that...").
  
  The Timberlake-Timbaland team were coming off Justin's FutureSex/LoveSounds album, with the hits "SexyBack" and "What Goes Around... Comes Around."
• Rihanna told Entertainment Weekly how this song came together: "Well, Timbaland was on tour with Justin and we had to follow Timbaland, really. So we went to Chicago first and one night after the show, Justin just came into the studio and he started messing around, making a beat. And it was fun. We played around with that one, too. And when we came to New York, Justin came back to the studio and he was like, 'I wanna write this song for Rihanna.' So Timbaland had an idea and he knew he wanted to call the song 'Rehab' and he had a beat. So then Justin Timberlake came in and he just put his thing on it. He wrote the song in his head. He didn't write anything on paper. He went into the booth and sang it and I was very, very impressed. We all loved it."
• "Rehab" was released on Rihanna's third album, Good Girl Gone Bad, in May 2007, but it didn't reach its chart peak of #18 until January 2009. Here's how it happened:
  
  Four singles were released from the album, starting with the rainmaker "Umbrella." These kept Rihanna on the radio for the rest of 2007 and into the beginning of 2008. Instead of releasing another album, Good Girl Gone Bad was then re-released with two additional singles, "Take A Bow" and "Disturbia," which both went to #1 that summer. That autumn, her T.I. collaboration "Live Your Life" blew up, also landing at #1. Rihanna's label, Def Jam, then commissioned a video for "Rehab" and put it out as a single, which carried her into 2009.
• In the music video, Justin Timberlake plays the brooding ex boyfriend who has Rihanna in a tizzy. It was shot in Vasquez Rocks Park in Los Angeles and directed by Anthony Mandler, who did most of Rihanna's videos around this time.