Britain's Prince William has started his paternity leave.

Britain's Prince William

Britain's Prince William

The 32-year-old royal - who is expecting his second child with his wife, the Duchess of Cambridge, any day now - has ended his Air Ambulance helicopter pilot training early to be close to the brunette beauty when she goes into labour.

According to the Daily Express newspaper, the prince won't return to his training until June 1 as his unpaid paternity leave also coincides with a series of royal engagements.

A spokesperson for Kensington Palace said: "The Duke of Cambridge has completed the first phase of his in-work air ambulance helicopter pilot training with Bond Air Services earlier than anticipated.

"This is due to a combination of the Duke performing well in the various modules and having very good flying conditions that allowed flight training and assessment to progress more quickly than had been planned.

"His final block of in-work training requires an uninterrupted three-week block of working time and the availability of the new EC145 helicopter that will be used for missions.

"As he now will not have any further training to complete after returning from paternity leave, he will not return to duties with Bond until that time, and will remain on unpaid leave until then."

The Duchess - whose due date is April 25 - is reportedly set to give birth in the Lindo Wing at St Mary's hospital in Paddington, London, where the couple's first child Prince George was born in July 2013.