Prince Harry has kept in touch with the Duke of Cambridge throughout his Diamond Jubilee tour, drawing on his older brother's experience.
Harry's first solo trip on behalf of the Queen which ends later has been seen as many as a success and brought the royal new admirers during his travels to Belize, the Bahamas and Jamaica.
Behind the scenes the prince has been chatting frequently with William by mobile phone and exchanging text messages with his sibling, said a source.
And before he set off for the major visit last week he sought the duke's guidance about how he dealt with overseas trips and took his advice on "how to mix the informality with the dignity of (representing) the Queen", a source added.
Harry has remained true to himself during the tour, bringing his sense and humour and fun to engagements over the past six days and also proving himself to be an adept public speaker like his father the Prince of Wales.
In Belize Harry enjoyed an exciting Diamond Jubilee street party and was swept up by the genuinely warm welcome from the locals who had him dancing with performers, tasting local food and even downing shots of rum. The Bahamas gave the prince the chance to join the country in formally honouring the Queen at a national service of thanksgiving.
Harry also charmed Jamaica's staunchly republican prime minister Portia Simpson Miller who plans to end centuries of constitutional ties with the British monarchy by replacing the Queen as head of state with a Jamaican.
The source said: "He spoke at length with his brother before coming out about how to approached it, and they have been in communication throughout the tour.
"They have been in touch regularly via mobile and text. The relationship they have is full of banter and humour, but Prince William is deeply caring of his younger brother and wants his younger brother to succeed."
Harry has made a lasting impression with the people of Belize, the Bahamas and Jamaica and they have got to know the Queen's grandson, while he has undoubtedly learnt something about them.
The prince was "very pleased with the reaction he got, the warmth of the welcome", and this prompted him to send messages of thanks to the Governor Generals of Belize and the Bahamas while still on tour, something that is normally done when a royal returns home.
The prince leaves Jamaica later for a three-day visit to Brazil where he will promote the UK on behalf of the Government when he arrives on Friday.