Did you hear the rumor that they stole this from the group Nephu? Check out what I found at Wikipedia:
“Same Girl” is a song released by R&B singer R. Kelly, from his 2007 album Double Up and features another R&B singer, Usher. It was previously recorded over a year ago by upcoming R&B group Nephu . R. Kelly & Usher’s version leaked to the internet on May 2nd, 2007 and later leaked to radio stations. It has been noted that the song was orginally written for R&B sensations Joe and Tyrese to do as a duet together. However Joe felt that It would be best suited for Usher and himself to record the song because they are labelmates. The track was allegedly recorded however it was never released. A few months later, this song was leaked, however it no longer contained Joe in the song. R. Kelly had now replaced him..
The video was shot on June 1st-3rd 2007.
It was also rumored that R. Kelly stole the song from Nephu, but Nephu states on their official myspace  that although they originally recorded the song over a year ago, they never obtained legal ownership of it. At this point Nephu will not be releasing “Same Girl” on their upcoming album on Sho’Nuff Records