BEVERLY HILLS, Calif. - Break out the cake: Another movie about Prince William and Kate Middleton is set to debut on TV.

Hallmark's "William & Catherine: A Royal Romance" premieres Aug. 27. In April, the Lifetime network aired the much maligned telefilm "William & Kate."

"We are not afraid to explore the real side of the relationship and the challenges," Dan Amboyer, who plays William, said while promoting the movie at a meeting of the Television Critics Association.

"Diana features in the film," Alice St. Clair, who portrays Middleton, said Wednesday. "There is just really a great sense of relationships within the family. So there is William's relationship with his father and his brother, and you see him calling upon Diana's interview, and watching this interview that Diana did and using her words to kind of guide him through his troubled moments."

The movie also features Victor Garber as Prince Charles, Jean Smart as Camilla Parker Bowles and Jane Alexander as Queen Elizabeth II.

But Kate's very popular sister, Pippa Middleton, is mentioned in the telemovie but does not appear. "JLo was busy, so there wasn't anyone else to play the part," St. Clair said jokingly, noting the famous derrieres of both Pippa Middleton and Jennifer Lopez.