Kate Middleton pregnancy announcement on the horizon, Prince William agrees to baby no. 4: source

Prince William and Kate Middleton may already be thinking of having another child after she has managed to convince him of going for baby number four.

A source told US Weekly that the mum-of-three "has been talking about wanting another baby for a while now. She has always wanted four children, and while William was originally happy with three, she has managed to twist his arm."

The insider added that friends of the couple "wouldn't be surprised" if the former Duchess of Cambridge will announce that she is pregnant with baby number four "early next year."

The Princess of Wales has been open to having another child and her husband knows how this feeling can heighten during adorable interactions with babies. In February, during a visit to Copenhagen, Denmark, she met two eight-month-old-baby boys and admitted that she gets "broody" when she sees babies.

She shared that Prince William always worries about her "meeting under one-year-olds" because she comes home saying "let's have another one."

During the same visit, she also got giddy as she cradled and rocked a baby girl in her arms. The Prince of Wales could only look at his happy wife and joke with photographers about not giving her any ideas.

Kate Middleton is reportedly hoping for baby number four because she feels that her children are growing up so fast. Her youngest, Prince Louis, already started school in September and "she wonders how empty things will feel when there are no little ones running around during the day."

It is said that she is hoping for another daughter. Royal author Katie Nicholl shared that the royal's interest in having a big family comes from her close bond with her siblings, Pippa and James, She said Kate Middleton has "always been extremely close to her sister" and that her children, Princes George and Louis, and Princess Charlotte are also "very close to Pippa and James' children."

Reports about baby number four for Prince William and Kate Middleton come after they moved their family from Kensington Palace to Adelaide Cottage in Windsor in September. The relocation is understood to benefit their children because there they can freely ride their bikes around the estate and have a normal life as much as possible.