Theatre-goers were in for a royally exciting surprise when then discovered they had a princess, in the form of Duchess Catherine, in their midst.
Prince George and Princess Charlotteโs mum dropped by the Royal Opera House on Wednesday to watch a performance of The Nutcracker.
The pregnant royalโs visit came just hours after the Queenโs Christmas lunch at Buckingham Palace.
The 35-year-old was snapped by eagle-eyed fans rocking her favourite outfit combo: a Zara cape and Alexander McQueen dress.
One audience member was delighted to get a glimpse of the expectant mum.
Taking to Twitter and sharing, โHighlight of todayโs nutcracker was trying to peer through a crack in the scenery to spot Kate Middleton in the crowdโ.
Meanwhile, ballerina for the Royal Ballet, Meaghan Grace Hinkis, got to meet the Duchess.
Sharing the moment on Instagram, the soloist penned, โTo say I was excited to meet the Duchess, is a colossal understatement!โ
Adding the hashtags: #thathairthough #iwanttobeaprincesswhenigrowup

The Cambridges at the Queenโs lunch.

How adorable is Charlotte!
After a bumpy start, suffering from hyperemesis gravidarum, the Duchess seems to be loving the later stages of her pregnancy.
One pal told Us Weekly, โ[She is] enjoying her later months of pregnancy and feeling great.โ
โItโs amazing what a difference the later trimesters feel like compared to the early days, which she really struggled with more than ever this time.โ