Forget the boys. Rihanna planning girls-only tour

Marc Malkin Rihanna

is planning a girls-only North American tour that will kick off in September.

Touring with her? Possibly

Keyshia Cole

, who are said to be in negotiations to join the tour. "Rihanna wants strong women to join her," Malkin's source says. "This is a 'women empowerment' type of tour."

No details yet on exactly when the tour will begin or where the show will go. (Sprint Center, Sprint Center, please.)

Rihanna, who's already in the studio working on a new album, will make her first solo stage appearance since her Feb. 8 altercation with ex-boyfriend

Chris Brown

next month in Dubai. Her last concert was Jan. 29 in L.A.

Reps for Rihanna and Ciara did not comment on the tour talk; Cole’s rep denied the speculation.

| Lisa Gutierrez, The Star