Kate Middleton, 35, has not been seen since it was revealed she was pregnant with her third child due to suffering severe morning sickness.
But tonight she made her first appearance in six weeks, and the Duchess of Cambridge glowed as she stepped in front of cameras.
A tiny hint of a baby bump could be seen, but there was otherwise no clue as to her condition.
Kate chose a delicate blue Temperley London lace dress, £795, for the evening at Buckingham Palace.
Kate joined her husband Prince William for the reception in aid of World Mental Health Day.
Her choice of a blue lace dress is sure to set tongues wagging that the Duchess is expecting a baby boy.
The dress came to Kate’s calves, and had a high neckline with a black velvet bow.
The sleeves featured delicate lace cuffs which came down over the top of the Duchess’ hands.
Small black buttons ran down the front of the dress, giving it a prim edge.
Kate paired her dress with a pair of high-heeled black court shoes and dazzling diamond drop earrings.
She carried a very small black clutch in one hand as she walked along beside Prince William.
She kept her makeup to a minimum, with a hint of blusher and precise eyeliner being the only thing visible.
As usual, Kate’s hair looked fantastic – possibly thanks to pregnancy hormones, and she wore it down in loose bouncy curls.
Both Prince William and his wife could be seen laughing and smiling as they spoke to guests attending the reception.
At times the Duchess cradled her growing baby bump, with her arms resting underneath it.
Prince Harry also joined the couple at Buckingham Palace, although there was no sign of his girlfriend, Meghan Markle, who was rumoured to be making an appearance.