Vampire romance Twilight opens in the UK on 19 December
Record-breaking Twilight director Catherine Hardwicke will now not direct its sequel, New Moon.
According to reports, the US film-maker felt that she needed more time to work on the film and could not commit to a late 2009-early 2010 release date.
"I am sorry that due to timing I will not have the opportunity to direct New Moon," said Hardwicke in a statement.
Producer Summit Entertainment said it had "a mandate" to release the next instalment "in a timely fashion".
"We are able to pursue an aggressive time frame as we have the luxury of only adapting the novels into screenplays, as opposed to having to create a storyline from scratch," said Summit's Erik Feig.
Based on the novel by Stephenie Meyer, Twilight tells of a young girl, played by Kristen Stewart, who falls in love with a vampire, played by Robert Pattinson.
The film has been hugely successful in the US, where it set a new record for the biggest opening weekend for movie directed by a woman.
Hardwicke, whose other pictures include Thirteen and The Nativity Story, said New Moon had "a great story" and sent Summit her best wishes.
No replacement for the sequel has been named, while the film has yet to announce when it will commence shooting.
Twilight, which had its London premiere last week, opens in the UK on 19 December.