Sienna Miller has joined the ensemble romantic comedy New Year's Eve.  According to The Playlist, the actress has agreed to join a ludicrously star-studded cast that features (take a deep breath): Robert De Niro, Jake Gyllenhaal, Ashton Kutcher, Jessica Biel, Halle Berry, Zac Efron, Sarah Jessica Parker, Michelle Pfeiffer, and Hilary Swank, just to name a few.

New Year's Eve is being directed by Garry Marshall, who also helmed the strikingly similar Valentine's Day only a year ago.  Katherine Fugate also returns to pen the film which isn't so much a sequel as it is a perfectly-timed box office jackpot.  As for Miller, details of her role are currently unknown.  Given the star power she is surrounded with, here's to hoping she can get a word in edgewise.  New Year's Eve is scheduled to begin shooting in New York in the near future and will hit theaters later this year on December 9th.