Associated Press

The former Kate Middleton has cancelled a planned appearance at the U.K. premiere of "The Hobbit" in London due to acute morning sickness.

Palace officials said Tuesday Prince William's wife, now known as the Duchess of Cambridge, will continue to rest rather than go to the show.

William still plans to go to the premiere.

Middleton has cancelled all public engagements since her brief hospitalization last week for severe nausea and dehydration. She is suffering from a condition known as hyperemesis gravidarum that causes sustained nausea and discomfort.

Her pregnancy is still in early stages.

"The Hobbit: An Unexpected Journey" is the first of three films by Peter Jackson based on the J.R.R. Tolkien classic.

The film stars Martin Freeman as the homebody Hobbit Bilbo Baggins while Ian McKellen reprises his "Lord of the Rings" role as the wizard Gandalf.

The movie opens in the United States on Friday.