House star Jennifer Morrison has joined the cast of The Murder of Princess Diana, a TV movie being produced by Working Title Television for the US cable channel Lifetime.

Morrison will play an American journalist who starts her own investigation after disbelieving the official version of Diana's death.

Lifetime's Susanne Daniels said that the movie is "sharing a dramatic story that will appeal to millions of people's continued fascination with both the facts and speculation surrounding the case."

Executive producer Simon Wright added that the film "raises some very difficult questions."

Lifetime plans to premiere the movie in August.