Kate Middleton is planning to have a royal baby no. 3.

Kate and Prince William have been reportedly planning to grow their family of four since they welcomed Princess Charlotte in 2015. "She wanted another almost since giving birth," a source told Us Weekly. The insider added that the Duke and Duchess of Cambridge postponed their third pregnancy because they realized that juggling their newborn and their eldest, Prince George, is not easy.

Now that Princess Charlotte is already 2, and Prince George is 4, the source believed that it is time for Kate and Prince William to continue their baby plans. "Now is definitely that time. They would love to be pregnant soon." Meanwhile, Kate's sister, Pippa, who just married hedge fund manager James Matthews in May is also "currently trying for a baby."

"It's long been a dream for Kate and Pippa to be pregnant at the same time," a Middleton family friend revealed. "To share that would be amazing."

The insider added that Pippa and Matthews have been talking about their future family even before they exchanged "I Dos." Pippa also discussed the possibility of getting pregnant at the same time with her older sister. "Pippa's always said how great it would be if they were to be expecting together," the source continued.

Since Kate and Prince William are moving in London in September, the Middleton sisters will be living closer to each other. Thus, if they get pregnant at the same time, they can be each other's support system in shopping for baby clothes and in attending pregnancy yoga classes.

The insider also added that the Middleton family is seeing Pippa leaning on Kate as the latter has more experience in pregnancy and in rearing a child. "Kate has so much knowledge to share. She's a walking baby encyclopedia at this point!" the source said.

Speaking of royal baby no. 3, Kate made headlines in July when she received a gift designed for newborns and joked to her husband, Prince William, that they "have to have more babies."

Some believed that it was a hint about royal baby no. 3 while others just accepted it as a mere joke. "I actually think the opposite! I expect she joked about it because it's not something they're serious about but never say never!" correspondent Victoria Murphy said.

Do you want Kate and Pippa to get pregnant at the same time? Drop a comment below.