The disappearing Duchess: Catherine returns from honeymoon looking slimmer than ever for meeting with Obamas

It's her first Royal engagement since her honeymoon.

So perhaps nerves have got the better of Catherine Middleton, who looked slimmer than ever when she met the Obamas at Buckingham Palace today.

Like most brides, the Duchess of Cambridge shed pounds ahead of her wedding to Prince William last month - but it appears her ten-day break in The Seychelles did little to increase her appetite.

The honeymoon's over: The Duchess of Cambridge didn't appear to have put any weight on during her trip to The Seychelles as she meets Michelle Obama in her first official engagement at Buckingham Palace today

Slender: Catherine wore a £175 Reiss 'Shola' dress in camel while Michelle opted for mint floral

Catherine, 29, showed off her tan in a knee-length shift dress by favoured label Reiss and a Maude clutch by Anya Hindmarch Bespoke.

In a nude £175 'Shola bandage' dress and sporting her signature blow dried-hair, Catherine looked the picture of elegance as she chatted with Michelle inside the palace.

Meanwhile, the U.S President's wife played it too safe, opting to wear a mint floral dress strikingly similar to the Queen's.

The Queen's patterned white dress is a trademark look, but Michelle's clashing outfit was a far cry from the pared-down elegance we have come to expect from the First Lady

Tanned: Britain's Catherine, Duchess of Cambridge looked exceptionally trim as she chatted to the U.S. First Lady

Pleasantries: The pair spoke in the Bow Room at Buckingham Palace after the Obamas had first met the Queen and Prince Charles

The faux-pas could perhaps be explained by Obama's nerves as she probably erred on the side of caution, choosing an outfit she knew would please the Queen.

The prom-style dress is from the resort 2011 collection by Barbara Tfank but was altered to remove the bow from the waistband.

The LA-based designer has dressed celebrities including Adele and Angeline Jolie and claims Obama 'loves my florals.'

Camilla opted for a cream suit by her trusted designer Anna Valentine and matching hat by Phillip Treacy, an outfit that would have been better suited to the Royal Wedding.

Despite Michelle's sartorial choice, Royal watchers say the Queen has taken a liking to the Obamas ever since meeting the couple during their 2009 visit to London.

Mrs. Obama created a stir in Britain when she wrapped her arm around the Queen - another faux pas, according to royal etiquette experts - only to have the Queen respond with her own show of affection and a reciprocal embrace.

The Obamas will spend two nights at Buckingham Palace after an elaborate arrival ceremony, and toasted at an intimate banquet for about 200 royals and other dignitaries this evening.