"This week, we look at one of Rihanna’s more polarizing songs – 2008’s “Rehab”, featuring Justin Timberlake. “Rehab” was released as the eighth and final single from Rihanna’s 2007 album “Good Girl Gone Bad” 10 years Ago, and was one of three songs which were composed by Timbaland (“Sell Me Candy” and “Lemme Get That” being the other two). Timberlake allegedly came up with the lyrics to the song in his head and improvised the track over Hannon Lane’s beat. 

In The "FutureSex/LoveShow" tour in 2007. Timberlake wrote the song in collaboration with his producers, Hannon Lane and Timbaland, and provided additional vocals. "Rehab" is a mid-paced R&B song with an emotional, melancholy chorus; the lyrics are about the protagonist's painful memories of her former lover, who is portrayed metaphorically as a disease.

Rihanna told Robert Copsey at Digital Spy that “working with Justin in the studio is just great. He’s a fun guy and likes to make all the sessions enjoyable. He’s also such a genius when it comes to lyrics.”
The influence of Timberlake was obvious, as “Rehab” is structured similarly to several other of his songs, including “Cry Me a River” and “What Goes Around…Comes Around”. According to Timberlake in an interview with Entertainment Weeklythe song was intended to help Rihanna become a more mature artist:
  • “She’s a young artist stepping into the adult world. To me, that song is the bridge for her to be accepted as an adult in the music industry.”

After completing a show in Chicago, they joined Rihanna in the studio, where Timberlake experimented with beats and melodies. Weeks later, the three got together in New York City, where Timberlake had already conceptualized a song for Rihanna. Timbaland, who wanted to compose a song called "Rehab" for Rihanna, was producing a beat, when Timberlake came in and improvised the song over it. Hannon Lane co-wrote and co-produced the song, and Demacio Castellon recorded and mixed it in 2007 at Roc The Mic Studios in New York City. 

Rihanna filmed the music video for "Rehab" with Justin Timberlake at Vasquez Rocks Park, near Los Angeles, on October 22, 2008. It was directed by Anthony Mandler, who directed the videos for Rihanna's 2008 singles "Take a Bow" and "Disturbia". Photographs of the production were leaked on the same day. Tim Nixon of The Sun wrote that the "red hot chemistry" between Rihanna and Timberlake must have been difficult for their partners to watch

Regardless of how the critics feel, however, you can’t deny how great RiRi looks in the music video. She looks incredibly seductive in a tantalizing green outfit as she leans against the hood of a a vintage car while she waits for Timberlake to approach. Seriously though, how good does JT have it? He only has to say a handful of lines while a stunning Rihanna grinds up against him. No wonder Jessica Biel was furious.