Kate's First Solo Interview on Queen's 90th Birthday Reveals Special Bond with Prince George and Princess Charlotte

"Its very special having a new little girl," Kate says in the ITV interview.

— -- The Duchess of Cambridge has done her first solo interview to pay tribute to Her Majesty on her 90th birthday. In the touching tribute to The Queen, Kate says she was thrilled that her fourth great grandchild was a little girl.

The Duchess also revealed Prince George's nickname for His great-grandmother: “George is only two-and-a-half and he calls her ‘Gan-Gan.’

The Queen has taken a special interest in her 3rd and 4th great grand children and apparently loves leaving them special gifts when they visit. "She always leaves a little gift or something in their room when we go and stay and that just shows her love for her family,” Kate said.

Talking about The Queen passing on her experiences to her, the Duchess of Cambridge was grateful for the interest and care as she navigates her way as a new member of the Royal Family. "She's been very generous in not being forceful at all and in any of her views, but I feel she's been there -- a gentle guidance really for me," Kate shared.

She says she's still learning the ropes but the Royal Family sometimes lovingly tease her. "I think there is a real art to walkabouts," she says. "Everyone teases me in the family that I spend far too long chatting. So I think I've still got to learn a little bit more and to pick up a few more tips I suppose.”

The Duke of Cambridge, Prince William, also contributed to the documentary paying tribute to his grandmother "Growing up, having this figurehead, having this stability above me has been incredible," he said. "I have been able to explore, understand, slightly carve my own path. I greatly appreciate and value that protection."

"Our Queen at 90" airs on Easter Sunday on ITV