R&B crooner Ne-Yo [ tickets ] has been dropped from R. Kelly [ tickets ]'s "Double Up" tour just a week into the outing.

R. Kelly reps have told various publications that Ne-Yo's departure stems from a contractual issue, but the singer doesn't seem to be convinced.

"I believe it was because the first few reviews of the show, people were talking more about my set than [Kelly's] and I don't think he liked that too much," Ne-Yo told BET.com.

In a statement from Def Jam Recordings, he added, "I am disappointed that I won't be able to perform for my fans. I love being on stage in front of fans because of the immediate feedback you get. You know right away if they are feeling you; and they were really feeling our show."

Ne-Yo was tapped to open the nine-week trek along with Keyshia Cole [ tickets ] and J. Holiday. The "Double Up" tour continues tonight in Philadelphia and visits arenas all over the US through mid-January.

Fans can still catch Ne-Yo on the Macy's Thanksgiving Day Parade, which airs tomorrow (11/22) on NBC-TV.

The Grammy-nominated performer is working to support his May release, "Because of You," which is his second No. 1 album on The Billboard 200. The set has spawned the singles "Do You," "Can We Chill" and the title track.

Ne-Yo (born Shaffer Smith) made a name for himself at a young age writing songs for multiplatinum-selling artists including Mary J. Blige, B2K, Faith Evans and Musiq, according to Def Jam. He co-wrote one of urban radio's most-played songs of 2004, "Let Me Love You," performed by R&B singer Mario, as well as Beyonce's No. 1 single "Irreplaceable."