• One sister, Savannah, two half-brothers, Charles and Stephen and a step-sister, Natasha.

• Her mother, Jo Miller, ran London’s Lee Strasberg drama school.

• Studied drama at the Lee Strasberg Institute in New York.

• For more than a decade her father, American Banker Ed Miller, was married to top interior designer Kelly Hoppen.

• Was educated at Heathfield School in Ascot, Berkshire.

• Her birthday is one day before that of ex-boyfriend Jude Law.

• She was born in the USA but raised in the UK.

• Met boyfriend Jude Law when they made the movie Alfie (2004) together.

• Named her two dogs Porgy and Bess after the two leading characters in Gershwin’s opera of the same name.

• Became engaged to Jude Law on Christmas Day, 2004.

• Studied acting with Michael Margotta.

• Jude Law publicly apologized for cheating on her with nanny Daisy Wright. [July 2005]

• In the summer of 2005, she made her West End debut in the stage production of William Shakespeare’s “As You Like It”, directed by David Lan, at the Wyndham Theatre. She played the role of Celia.

• Ended her seven-month engagement with Jude Law. [Late July 2005]

• Her sister celebrates her birthday two days after Sienna’s.

• Named #48 on the Maxim magazine Hot 100 of 2005 list.

• Named #2 in AskMen.com’s Top 99 Most Desirable Women

• Ranked and Voted #2 by AskMen.com’s Top 99 Most Desirable Women of 2006

• She and co-star Hayden Christensen shared a house during the filming of Factory Girl (2006) in Louisiana.

• #42 on maxims hot 100 of 2006

• Lost out on the role of “Lureen Twist” in Brokeback Mountain (2005) to Anne Hathaway.

• Named #63 in FHM magazine’s “100 Sexiest Women in the World 2006″ supplement. (2006).

• Broke up with Jude Law, again [November 13, 2006].

• Fan of Chelsea FC (England football club).

• Told “The Daily Telegraph” newspaper in February 2007 that she has tried to quit smoking, but “it’s so hard.”.

• Replaced Lindsay Lohan for the role of Caitlin MacNamarra in The Edge of Love (2008) starring alongside her close friend Keira Knightley.

• Ranked #11 on the Maxim magazine Hot 100 of 2007 list.

• Was named “Film Actress of the Year” at the 2007 Glamour Women Of The Year Awards.

• Ambassador for Global Cool.

• Sister of Savannah Miller, a graduate of the prestigious Central St. Martins Design School.

• Received an unprecedented $75,000 settlement when a British court ruled that British tabloids the “Sun” and the “News of the World” had violated her invasion of privacy rights. The tabloids had covertly photographed Miller doing a nude scene in the production Hippie Hippie Shake (2010), and later published the pictures without prior permission. [2007]

• Good friends with Guy Pearce, Keira Knightley and Anne Hathaway.

• Though New York-born, Miller grew up in south-west London’s Parsons Green district.

• Sharing a house with Welshman Rhys Ifans in London’s St. John’s Wood district. [2008]

• Mother Jo Miller worked for David Bowie for a spell during the 1970s.

• Ranked #27 on the Maxim magazine Hot 100 of 2008 list.

• Broke off her engagement to Rhys Ifans. [June 2008]

• Rhys Ifans had to ask her three times to marry him before she finally said “yes”.

• Vacationed with boyfriend Balthazar Getty in Italy’s Amalfy Coast. [July 2008]

• Campaigned for the role of Stephanie Necrophuros in Nine (2009), but Kate Hudson was given the part instead.

• Was originally cast as Maid Marian in Robin Hood (2010) before being replaced by Cate Blanchett.

• Passed her U.K. driving test [July 11, 2009].

• Were considered for the role of Queen Gorgo in 300 (2006).

• Sienna sprained her wrist while filming a fight scene in G.I. Joe: The Rise of Cobra (2009) between she and Rachel Nichols.