"Past Life Regression Therapy" may be legit, but the reality show Have I Been Here Before is ludicrous.
PLRT is based on the assumption that our past lives haunt us, and that drawing them forth through hypnosis and exorcising them can help resolve problems in this life. Then there's the show. Here's how it works: a celebrity (not A-list) goes under hypnosis, and then "experts" "analyze" the "findings" and put together a probably historical character for said celeb.
Even if you're convinced by the celebrities' "revelations," the absurdity of the show itself — from the creepy, portentious host, to the historical recreations, to the smoke machine — give it all the credibility of a Disneyland ride circa '74.
That said, in the words of the show, "judge for yourself!" After all, a Daily Mail reporter undergoes a session and discovers an 18th Century soldier named Nathaniel in her past.
Sacre Bleu! Have I Really Discovered My Past Lives? [Daily Mail]