Royal author ANDREW MORTON is planning a reveal-all biography of Hollywood superstar Tom Cruise.

Morton - who caused massive controversy in 1992 with a similar book about DIANA, PRINCESS OF WALES - plans to delve into Cruise' religious upbringing and his engagement to Katie Holmes.

A source tells British newspaper the Daily Express, "Andrew has been doing research for the book in Los Angeles. It obviously has the makings of a best-seller."