Kate and William show off their baby son!

The Duke and Duchess of Cambridge proudly showed the world their baby son, a future king, before taking him home tonight.

William and Kate began their new lives as parents, cradling their baby prince and posing for pictures on the steps of the Lindo Wing of St Mary’s Hospital in London.

The Duchess held her son first and the couple looked relaxed and smiled broadly as the world’s media captured the moment.

William later held his son and walked forward with his wife to answer a few questions. He began by joking: “He’s got a good pair of lungs on him, that’s for sure. He’s a big boy, he’s quite heavy. We are still working on a name so we will have that as soon as we can.”

He added: “It’s the first time we have seen him really so we are having a proper chance to catch up.”

The Duchess, who still had a bump under her summer dress, said: “It’s very emotional, it’s such a special time. I think any parent will know what this feeling feels like.”

Her husband agreed: “It’s very special.”

He added: “I’ll remind him of his tardiness when he’s a bit older. I know how long you’ve all been standing here so hopefully the hospital and you guys can all go back to normal now and we can go and look after him.”

Speaking outside hospital, William said: “He’s got her looks, thankfully,” while Kate replied: “No, no, I’m not sure about that.”

Joking about his apparent lack of hair the Duke said about his son: “He’s got way more than me, thank God”.

The couple’s good humour continued during their brief questioning from the press with Kate revealing that her husband was a hands on dad.

Asked about changing nappies William said: “We’ve done that already,” and Kate said, “he’s done his first nappy already”.

The Duke looked at ease holding his son and after speaking to the press for a few minutes returned inside the Lindo Wing with his wife.

The couple soon emerged with their son in a baby seat and William carefully fitted it onto the backseat of a Range Rover beside his wife before driving his family home.

The baby was born on Monday, which could hardly have been a more appropriate day for a new addition to the British royal family – if you’re Israeli that is!

Tu B’Av, the Jewish state’s holiday of love, fell on the same day as the Royal delivery as couples, suitors and secret admirers celebrate their love on what has come to be known as the “Jewish Valentine’s Day”.

So as the Duchess of Cambridge welcomed a baby boy weighing 8lb 6oz  at 4.24pm, Israelis were marking their special day of love with gifts, flowers and cards.

Confirmation of the royal birth arrived by car in the form of an official statement, carried by the Duke and Duchess of Cambridge’s press secretary.

William and Kate stayed overnight at St Mary’s Hospital in London and already well-wishers and media from across the globe are gathering outside the building in anticipation of seeing the new baby.

A smiling David Cameron declared the birth “an important moment in the life of our nation”.

Speaking outside 10 Downing Street, the Prime Minister said last night: “It is wonderful news from St Mary’s, Paddington, and I am sure that right across the country, and indeed right across the Commonwealth, people will be celebrating and wishing the royal couple well.

“It is an important moment in the life of our nation but I suppose above all it is a wonderful moment for a warm and loving couple who have got a brand new baby boy.

“It has been a remarkable few years for our Royal Family – a royal wedding that captured people’s hearts, that extraordinary and magnificent Jubilee and now this royal birth – all from a family that has given this nation so much incredible service.

“They can know that a proud nation is celebrating with a very proud and happy couple tonight.”

American President Barack Obama and his wife Michelle, who has developed a close relationship with the Queen, also spoke of their joy at the birth.

The US leader said: “Michelle and I are so pleased to congratulate the Duke and Duchess of Cambridge on the joyous occasion of the birth of their first child.

“We wish them all the happiness and blessings parenthood brings. The child enters the world at a time of promise and opportunity for our two nations.

“Given the special relationship between us, the American people are pleased to join with the people of the United Kingdom as they celebrate the birth of the young prince.”

Kate was admitted to the Lindo Wing just before 6am yesterday in the early stages of labour.

She had planned for a natural birth and had at least 10 and a half hours of labour before her baby was born. Kensington Palace said it “progressed as normal”.