Mann, the current Shark Fights featherweight champion is 7-1 in his last 8 fights. He lost to Hatsu Hioki via submission in the second round of SRC's featherweight grand prix in May 2009.
The 24-year-old British fighter had expressed interest in signing with WEC last year, but no deal was ever finalized. His featherweight title win over Doug Evans was his first fight in North America in 21 professional fights.
No date or opponent has been signed for Mann's Bellator debut.
According to Rebney, Joe Warren, the current Bellator 145-pound champion, will compete in a non-title fight against a yet-to-be signed opponent on April 16. Rebney said Warren still hopes to compete in the 2012 Summer Olympics.
"We are going to support him and hopefully he can pull it off," he said.