PICS: Sienna Miller and her baby bump film advert in London

The actress has been spilling more details about her pregnancy

Sienna Miller and her fast-growing baby bump - which seems to be burgeoning at the speed of light - were hard at work filming an advertisement in London yesterday.

The 30-year-old actress was spotted on location in the capital working a number of typically stylish looks as she showed off her expanding stomach.

CONFIRMED: SIENNA MILLER IS PREGNANT

She looked achingly cool in a striped Breton top, skinny jeans and ankle boots as she worked it for the camera, before changing into a flowing white summer dress.

Miller, who is expecting her first child with boyfriend Tom Sturridge, 26, hasn't slowed down one bit since becoming pregnant and last month was seen filming scenes for new movie A Case of You in New York.

Although she is refusing to give too much away about her pregnancy and private life in general, she did recently reveal that she's developed a severe sweet tooth now that she's a mum-to-be.

'I feel very grounded, more than ever – it’s a wonderful feeling. But all of a sudden, I’ve started to get cravings,’ she said, explaining she wanted a vanilla ice-cream topping for her brownies.

‘I usually don’t have a sweet tooth but these tarts I could eat all day long!’ she added.

SIENNA MILLER'S AMAZING STYLE HISTORY

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