Selena Gomez and Adam Lambert are rumored to be organizing a tour to go head-to-head with the one now being promoted by Demi Lovato and Nick Jonas.

According to Celebrity Dirty Laundry, earlier this month it seemed like a done deal that Lovato and Lambert would hit the road together. Their two camps were working out the final details like lighting, billing and payment. But at the last minute, Lovato announced she was replacing Lambert with Jonas, reportedly prompting a rivalry among the singers.

Lambert was rumored to be outraged by the switch, which many in his camp branded as "very unprofessional and unethical."

Lovato and Jonas are repped by the same manager, and word is the boss wanted to take advantage of Jonas' rising popularity with a tour right away.

Meanwhile, speculation conitues to fester that Gomez and Lovato are no longer as close as they once were. Not so long ago, the two were virtually inseparable. But, after Lovato went to rehab, she soon began distancing herself from most of her former party pals. Rumors also percolated that Lovato and Gomez may have fallen out over Lovato's dislike for Gomez's ex Justin Bieber.

Just weeks ago, the two were snapped in pics together that landed on social media and briefly fueled rumors of a reconciliation, before Lovato flat out told a reporter the two were not friends and were not on speaking terms.

In an additional twist, Gomez and Jonas spent time "hanging out" earlier this summer, before he was suddenly seen on the arm of Kate Hudson.

Through it all, Lovato and Jonas are said to have remained great pals, with the former "X Factor" judge having grown quite protective of him.