Kate Middleton was joined by Prince William in a private box at a performance of Kooza at the Royal Albert Hall
Kate Middleton celebrated her 31st birthday with a trip to the theatre, to see a performance of Cirque Du Soleil's spectacular Kooza, it has been revealed.
According to reports, the Duchess of Cambridge was joined by her closest friends and family for the evening out at the Royal Albert Hall, organised by her doting hubby Prince William.
KATE MIDDLETON'S 'PRIVATE' BIRTHDAY CELEBRATIONS
Onlookers reveal the royal party arrived to watch the performance in a private box, with pregnant Kate Middleton looking 'happy and radiant,' as she took in the circus show.
The relaxed birthday girl was spotted clapping and laughing during the sell-out spectacular, sitting next to Prince William, who wore glasses to take in the evening's events.
It's not know how Kate celebrated her 31st year during the day, although insiders revealed there may have been a small lunch or dinner for the Duchess's closest pals.
'Wills and the Middleton family are planning a very quiet do, but there'll be a 'surprise element', which could be one of two things,' one insider revealed.
'They'll arrange a very small lunch with present openings if she's feeling up to it. Or, they'll throw a big family dinner in the evening.
'She'll just want to be with her family and enjoy her last birthday with Wills before there's a little one to look after. And it seems Kate is just looking forward to spending her birthday with her family before she gets to grip with motherhood.'
A spokesman at St James's Palace simply said the Duchess would be marking her birthday 'privately'.
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