Kate Middleton and Prince William plan baby No 2!
Kate Middleton hopes to be pregnant again by next summer
Prince Harry was born two years and two months after Prince William
There is ninety months difference between Kate Middleton and Pippa Middleton
Prince William left pregant Kate William to play polo with brother Harry at the weekend
We're told Kate Middleton, 31, is determined to have her kids close together in age and wants to get pregnant again by mid 2014.
'She's so happy about becoming a mother that she's ready to have back-to-back babies,' explains a long-time friend of the Royal couple.
'After she got over the terrible morning sickness at the beginning of her pregnancy, Kate found it a breeze and totally loved carrying William's child.
'Now both Kate and Wills think it'd be fantastic for her to get pregnant again as soon as possible.
'And as far as she's concerned, that means giving herself the rest of 2013 to recover from this birth before trying for another baby in the New Year.
'The hope is that she falls pregnant by next summer.'
By that time the couple - and little Baby Cambridge - should be well settled into Apartment 1A at Kensington Palace, which they're currently renovating.
They're hoping to move into the 21-room home by the end off the year.
She's also keen to have as small a gap between her kids as possible.
Carole, 58, fell pregnant with Pippa around 10 months after having Kate, meaning there's only 19 months between the sisters.
If Kate were to fall pregnant by her target of June, the gap between her children would be 20 months.
William, 31, is also said to feel strongly about having back-to-back babies.
The gap between him and younger brother Harry, 28, is slightly bigger, though - it's two years and two months.
The friend tells us: 'Kate and William want to get on with it and have another one as soon as possible.
'She likes the idea of producing an "heir and a spare" just a few months apart.
'Besides, she doesn't want to spend ages working hard to get her figure back after the baby's born only to get pregnant again.'