Pregnant Sienna Miller shows off blossoming bump in unexpected dress

The British actress Sienna Miller left fans delighted after she unveiled her third pregnancy to the world while appearing at the British Fashion Awards on Monday.

Now the news is out, the Layer Cake star, 43, has no qualms about flaunting her blossoming baby bump as she did on Thursday evening in a rather striking dress!

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© Jed Cullen/Dave Benett/Getty Ima

Attending the PAFF charity event at a secret London venue, Lost, Sienna looked divine rocking a daring leopard print maxi dress, perfectly flattering her growing bump.

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© Jed Cullen/Dave Benett/Getty Ima

She swept her long blonde locks back into a stylish, messy ponytail. And, as for her glam, the mother-to-be opted for a face of natural yet camera-ready makeup comprised of fluttery lashes, subtle brushes of rosy blusher and nude lipstick.

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© Jed Cullen/Dave Benett/Getty Ima

Sienna posed with model Jessica Clarke, 32, who is engaged to her friend Dave Gardner.

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© Jed Cullen/Dave Benett/Getty Ima

The New Zealand-born model looked beautiful wearing a burgundy minidress adorned with gold lace.

Sienna's incredible reveal

The fun night out came just hours after Sienna made headlines, along with Ellie Goulding,  for both revealing the joyful news they are expecting on the red carpet of the British Fashion Awards.

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Sienna, who is expecting her second child with her boyfriend Oli Green, looked angelic, wearing a floor-length chiffon Chloe gown with a pair of white knickers and her baby bump fully on show. Completing her look were a pair of statement drop earrings.

This time, the Anatomy of a Scandal star chose mermaid-like waves as her go-to style for the evening.

© Getty Images

Meanwhile, British pop star Ellie, 38, who is already the mum to son, Arthur, whom she shares with her ex-husband Caspar Jopling, chose a tailored black capri pant, which she paired with a simple black crop top, allowing her beautiful bump to be shown. 

Completing her look, she added a leather trench coat and pointed-toe pumps.  This will be Ellie's first child with her boyfriend, Beau Minniear, 28.