Sienna and Savannah Miller Twenty8Twelve pop up shop launch.jpgIT'S TRUE! Sienna Miller has confirmed that she is pregnant with her first child with her boyfriend Tom Sturridge. Well her sister at least has confirmed the news. Savannah Miller told Vogue UK this morning that her sister is "is doing really well and we are all really happy about it, Tom is an amazing guy."

Sienna's step mother, Kelly Hoppen, also confirmed the exciting news but denied that the couple are engaged. "Sienna is definitely not engaged or getting married... she is pregnant," she told the Evening Standard.

Rumours that the actress was expecting a baby began to swirl earlier this month. They reached fever pitch after she and Savannah announced they were leaving Twenty8Twelve, the fashion label they founded six years ago. Savannah, who has two children with husband Nick Skinner, has since taken to Twitter to refuse claims that they stepped down because of their families.

"Just for the record we didn't step down at twenty8twelve because of our babies," she recently tweeted.

Congrats to the happy couple!