Kate Middleton couldn’t be more thrilled to have welcomed a baby girl into her family last May. The Duchess of Cambridge and mother of two opened up about having a daughter in a new documentary honoring Queen Elizabeth ahead of her 90th birthday April 21.

“It’s very special having a new little girl,” Middleton said during a solo interview for ITV’s “The Queen at 90” (via People magazine). “I feel very, very lucky that George has got a little sister.”

Middleton, who’s married to Prince William, said the queen was “really thrilled” when she and her husband welcomed Princess Charlotte.

“I think as soon as we came back here to Kensington she was one of our first visitors here,” she said.

In the documentary, which includes other members of the royal family and airs March 27 on ITV, Middleton revealed that her 2-year-old son calls the queen “gran-gran.”

“She always leaves a little gift or something in their room when we go and stay,” Middleton dished. “That just shows her love for her family.”

As previously reported, Prince William gushed about having a baby girl telling reporters last month at a rugby match in Wales that his daughter was “very easy” and “very sweet.”

“All the fathers say to me, ‘Just you wait, when they get to 9 or 11 they get crazy,’” he joked. “I’m looking forward to it. There will be some drama.”

According to E! Online, the Duke of Cambridge added that things have been going “very well” since he and his wife welcomed their new addition to the family. “No broken bones so far,” he said. “But they’re trying, running around and pushing things and jumping.”