The Duchess of Cambridge has given birth to a boy after being admitted to hospital in labour, Kensington Palace has announced.

Kate was taken to the private Lindo wing of St Mary's Hospital in Paddington, London, this morning as she prepared to give birth to her third child.

The baby prince will be fifth in line to the throne, the Queen and the Duke of Edinburgh's sixth great-grandchild and a younger brother 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 duchess is being cared for by consultant obstetrician Guy Thorpe-Beeston, who is the surgeon-gynaecologist to the household, and consultant gynaecologist Alan Farthing, the Queen's surgeon-gynaecologist - part of the trusted team who delivered George and Charlotte.

For her previous births, Kate had a 23-strong team of top medics working or on stand-by from Imperial College Healthcare NHS Trust - which runs St Mary's Hospital.

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.

Just like with her first two children, Kate had hoped for a natural birth and did not know whether she was having a boy or a girl.

Predicted names include Arthur, Albert, Frederick, James and Philip.

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.

But it depends how quickly Kate wants to head home.

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.

William and Kate have now followed 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.