Fifty Shades of Grey Casting: Will Robert Pattinson and Kristen Stewart Reunite for the Film?

The debate over the casting of the film version of EL James's best-selling erotic novel, Fifty Shades of Grey, continues.

Twilight heartthrob couple Robert Pattinson and Kristen Stewart are reportedly being considered for the lead roles of Christian Grey and Anastasia Steele.

It was recently announced that the film version of the book will be released in North America on 1 July 2014. British visual artist and film-maker Sam Taylor-Johnson will direct the movie.

The 27-year-old Remember Me actor recently set tongues wagging after inviting James to a party he hosted - a Great Gatsby-themed birthday party for friend and Arbitrage director Nick Jarecki.

"Rob and Kristen will both have to audition like everyone else, although they are bang at the top of director Sam Taylor-Johnson's wish list," a senior source at production company Focus Features told Daily Star, "They are virtually guaranteed to stimulate huge box office interest."

However, the couple's reunion is very doubtful, as the two broke up last year after it was confirmed that Stewart had cheated on Pattinson with British director Rupert Sanders. However, they reunited to promote The Twilight Saga: Breaking Dawn - Part 2.

"We are definitely looking towards a franchise. And with five Twilight films under their belts, Rob and Kristen have already proved they can carry a big-budget series. The way we are looking at it, their previous personal problems might make things awkward at first on set," the insider added, "But their high-profile romance and headline-making break-ups will definitely add some more spice for fans."