Prince George can be seen beaming on his grandfather's lap, while Camilla gestures for Princess Charlotte to look at the camera.
The Duchess of Cambridge smiles as she holds Prince Louis in her arms next to a proud Prince William.
The Duke and Duchess of Cambridge laugh beside one another.
Chris Jackson said: “I was delighted to have been asked to take these portraits of The Prince of Wales surrounded by his family to celebrate the important milestone of his 70th Birthday. It was particularly special to capture such an informal and relaxed family portrait over a fun afternoon in the gardens of Clarence House.”
On the same day, Prince Louis, Prince Charles and Kate took separate photographs which were released earlier this month.
The doting grandad gazes adoringly at the Duchess of Cambridge and Prince William’s youngest child, as they stand in the garden of Clarence House.
The snap, taken in September, shows Baby Cambridge being held in his mother's arms, giggling and cluthching his grandfather with his little hands.
The Royal Family are set to celebrate Charles' 70th with a bash thrown by wife Camilla.
HRH was also celebrated in a new BBC documentary, Prince, Son and Heir: Charles At Seventy, that showed the future monarch in "new light", with footage showing the royal swinging his grandchildren by their hands.
Prince William spoke candidly about his dad admitting he wished he was able to spend more time with the children.
“I think he does have time for it, but I would like him to have more time with the children."
Prince Charles has previously opened up about being a granddad, saying: "It's a different part of your life. The great thing is to encourage them. Show them things to take their interest."
"My grandmother did that, she was wonderful." He added: "It is very important to create a bond when they are very young."
“I think he’s…now he’s reached his 70th year it’s a perfect time to consolidate a little bit cause as most families would do, you are worried about having them around and making sure their health’s okay, and he’s the fittest man I know but equally I want him to be fit until he’s 95 you know going on."
“So, having more time with him at home would be lovely, and being able to you know play around, err, with the grandchildren."
“Cause when he’s there, he’s brilliant. But we need him there as much as possible.”
Charles' youngest son, Prince Harry, also spoke in the documentary.
Harry says: “I asked him to and I think he knew it was coming and he immediately said, ‘Yes, of course, I’ll do whatever Megan needs and I’m here to support you.’ “
“For him that’s a fantastic opportunity to step up and be that support, and you know he’s our father so of course he’s gonna be there for us.”
But one of the most heartwarming details is that the Prince of Wales reads his grandchildren Harry Potter.
"He reads Harry Pitter and he can do all the different voices and I think children really appreciate that."