Royal Christening Fashions are Cream de la Dream

— -- It may have been Prince George's big day, but fashionistas were more interested in what everyone was wearing to his christening at St. James Palace.

A relaxed-looking Kate wore an Alexander McQueen cream suit (Sarah Burton, of McQueen, designed her wedding dress) and a matching Jane Taylor hat. Her younger sister, Pippa, also sported cream, in a coat by British designer Suzannah Crabb.

ABC News Royal contributor Victoria Murphy says the sisters would have known that their outfits would be closely watched.

"Kate and Pippa knew all eyes would be on them today and, in particular, what they chose to wear," she says. "There's no doubt they would have put a great deal of thought into their outfits and, as usual, both looked great in knee-length day dresses perfect for the afternoon christening."

Read: World Gets Glimpse of Prince George at Royal Christening

Murphy adds that the Middleton sisters made sure to have their outfits complement each other.

"They managed this well by both wearing the same color," she says. "Their clean, chic and understated cream outfits were also a perfect match for Prince George's christening robe."

Kate's mum, Carole, wore a navy coat by Catherine Walker, topped off with a straw hat by milliner Jane Corbett. "Following on from her winning outfit at the royal wedding, she chose a colourful deep blue number that fitted in well with the queen's choice of sky blue," says Victoria Murphy. "It's no secret that Kate sometimes shares clothes with her mum so, who knows, we may see this outfit on the duchess at some point in the future!"

See: The First Official Images of Prince George

The queen wore a sky-blue cashmere coat with mother of pearl buttons by Stewart Parvin. She wore a brooch that her parents, King George VI and Queen Elizabeth, gave her to mark the birth of Prince Charles in 1948.

But it was Prince George who stole the show in a lace and satin gown. The original royal robe was made in 1841 for the christening of Queen Victoria's eldest daughter, Victoria, Princess Royal.

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The original gown has since been worn by babies at all royal christenings including the queen, her children and nearly all her grandchildren, including Prince William. In 2008 the queen commissioned Angela Kelly to make a hand-made replica in order to preserve the original, which had become too fragile.