Her Royal Highness The Duchess of Cambridge has been admitted to St Mary’s Hospital, in Paddington, London, in the early stages of labour.

Catherine, Duchess of Cambridge, was taken by car from Kensington Palace to the Lindo Wing of the hospital with The Duke of Cambridge, Prince William, this morning.

The couple are expecting their third child.

Prince George and Princess Charlotte were both born in the exclusive unit, as were their father, the Duke of Cambridge, and uncle, Prince Harry.

The baby prince or princess will be fifth in line to the throne, the Queen and the Duke of Edinburgh’s sixth great-grandchild and a younger brother or sister for Prince George and Princess Charlotte.

Kensington Palace said: “Her Royal Highness The Duchess of Cambridge was admitted to St Mary’s Hospital, Paddington, London, earlier this morning in the early stages of labour.

“The Duchess travelled by car from Kensington Palace to the Lindo Wing at St. Mary’s Hospital with The Duke of Cambridge.”

The couple have chosen not to be told the gender of their third child until he or she is born.

Just like with her first and second children, Kate is hoping for a natural birth.

Bookies believe Kate will have a girl and a large number of punters have placed bets on the baby being named Mary, the favourite with firms like William Hill and Coral.

Predicted names include Alice, Alexandra, Elizabeth, Mary and Victoria for a girl and Arthur, Albert, Frederick, James and Philip for a boy.

Once news of the birth has been announced on the official Kensington Palace Twitter and Instagram accounts, a bulletin notice declaring the birth will go on display on an easel in the forecourt of Buckingham Palace.

Consultant obstetrician Guy Thorpe-Beeston and consultant gynaecologist Alan Farthing will be among the team helping the duchess.

The two senior medics were involved in helping to deliver Kate’s previous children.

Mr Farthing, the Queen’s surgeon gynaecologist, was engaged to BBC presenter Jill Dando when she was shot dead on her doorstep in April 1999.

Mr Thorpe-Beeston, surgeon-gynaecologist to the Royal Household, delivered Princess Charlotte in 2015.

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With the baby on its way, press pens will now open outside the hospital as journalists, photographers and camera crews wait for confirmation of the baby’s arrival.

Royal watchers will be expecting a swift delivery.

With George, the duchess gave birth 10-and-a-half hours after being admitted to hospital, but Charlotte was born just two hours and 34 minutes after Kate arrived at the Lindo Wing.

George and Charlotte may visit the hospital to see their mother and baby sibling, just as George did when his younger sister was born three years ago.

While Kate is in labour, George and Charlotte are likely to be cared for by their full-time, live-in nanny, Maria Teresa Turrion Borrallo.

The duchess’s pregnancy was announced by Kensington Palace on September 4 last year.

Kate again suffered from extreme pregnancy sickness hyperemesis gravidarum.

She went on maternity leave on March 22, but the duchess - and her large bump - attended an Easter Sunday church service in Windsor with the royals on April 1.

She has joked that William is “in denial” about having a third child.

Although the Queen has four children, the duke is the first future king to have a third for more than 120 years.

In 1897, George V, then the Duke of York, welcomed a daughter - Princess Mary - the younger sister of Edward VIII and George VI.

Unlike William, George V never expected to be king and only became heir to throne when his older brother, the Duke of Clarence and Avondale, died from flu in 1892.

If the baby is a boy, William and Kate will be following in the footsteps of the Queen and the Duke of Edinburgh, who had a son, a daughter and then another son.

But the Queen and Philip also went on to have a fourth child - Prince Edward.