TV Guide reports that the former Heroes star will play Max Armstrong in a forthcoming episode.
The "regal, arrogant [and] self-important" character will become the prime suspect in a murder and will attract the attention of Patrick Jane (Simon Baker) due to his "calm, cold and collected demeanor".
Owain Yeoman, who plays arson specialist Wayne Rigsby on the crime drama, revealed that he is a fan of Coleman.
"I'll always remember him as Steven Carrington on Dynasty," he said.
The Mentalist returns to CBS on September 23. Coleman's episode will air on October 14.