The Duke of Cambridge is set to join the East Anglian Air Ambulance which is based at Cambridge Airport.
Prince William will begin a civilian pilot course next month followed by dedicated 999-response training.
If successful he will join the rescue team in a full time role next spring.
The role will be his main job but his roster will take into account the duties and responsibilities he will continue to undertake on behalf of the Queen.
He will be paid a salary which he will donate in full to the charity.
A Kensington Palace spokesman said the Duke is "very much looking forward to" the next step in his career.
Click below to watch a clip of Patrick Peal:
The Duke will fly missions in Norfolk, Suffolk, Cambridgeshire and Bedfordshire.
As new parents, William and Kate are expected to split their time between their new home at Anmer Hall near Sandringham in Norfolk and their apartment at Kensington Palace.
Before beginning the new job, William will be required to gain an air transport pilot licence to complement his military training and undergo training specific to his new role.
In order to gain this licence, he must complete five months of training followed by 14 exams and a flight test.
Initially he will be employed as a co-pilot but, after a period of training, William will be qualified as a helicopter commander.
The news strengthens William's ties with Cambridge after he completed a 10-week agricultural course at the University of Cambridge earlier this year.