Samantha Cameron and Michelle Obama were both impeccably dressed as they stood alongside their powerful husbands for the official photo last night at the White House state dinner in Washington, DC.

The Prime Minister’s wife wore a dress by London-based Italian designer Alessandra Rich.

Sam’s gorgeous blue lace ¾-length-sleeve belted dress from the Spring 2012 collection was paired with black heels from Next.

The First Lady opted for a gown by British-born, American-based designer Georgina Chapman, by donning Marchesa.

Michelle’s off-the-shoulder silk gazar draped column teal gown was teamed with a stunning Tom Binns statement necklace.

This portrait neckline with a statement necklace is a familiar look for Mrs O, as she sported a similar look back in May last year for the Royal dinner.

I think they both look outstanding. I love the modern electric-blue gown on Sam and Mrs O looks so effortless, classic and regal.

On this occasion I couldn’t pick a favourite.

Can you?

Credit: AlessandraRich.com & Mary F. Calvert/ZUMAPRESS.com