Kate Middleton Attends 'War Horse' U.K. Premiere; Celebrates 30th Birthday Monday

Kate Middleton UK War Horse Premiere - P 2012
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Kate Middleton UK War Horse Premiere - P 2012

The WWI film moved the Dutchess of Cambridge to tears, says director Steven Spielberg.

Dutchess of Cambridge Kate Middleton and her husband Prince William attended to U.K. premiere of War Horse Sunday in London.

And, according to director Steven Spielberg, the WWI picture brought the new royal to tears. He told the BBC, "I was sitting next to her. All I know is that at one point my wife, who was sitting to my right, right in front of my face she passed a Kleenex to the Dutchess of Cambridge.

PHOTOS: The Making of War Horse

"I just saw the Kleenex cross my face and I saw it arrive and stop, but I didn't want to intrude on her experience watching War Horse so I never glanced over."

The event took place at the Odeon cinema in Leicester Square, followed by a charity dinner.

On Monday, Middleton celebrates her 30th birthday -- her first as part of Britain's royal family.

PHOTOS: Royal Wedding Photos

Party plans include an '80s-themed bash complete with cocktails and karaoke at a secret location, notes Buzz Media's royal watcher Mark Hayball. The event, to be attended by family and close friends, "shall allow Kate and William to let their hair down and relax prior to his planned military tour to the Falkland Islands and the run up to the Queen’s Diamond Jubilee," writes Hayball.