Workaholic Jamie Oliver is one of Britain's wealthiest men (the recent Sunday Times Rich List estimated his fortune at £150 million) while his teenage sweetheart Jools, 37, runs family life between their two homes in Primrose Hill and Essex - and has now designed a kids' clothing collection for Mothercare.
In a cover interview in this month's Red magazine Jools admitted "There is no let-up with four kids."
"I don't want to stop. I want a fifth, but I know it would be wrong. I never get any time to spend with Jamie as it is. He has said, give it a couple of years, then maybe we can think about it..."
In the meantime her new baby is the Little Bird collection for Mothercare. Talking to Lauren Laverne, Jools said: "I have always wanted to do a kids' clothing range. When Mothercare came to us, I thought, well, I already shop there, my mum shops there... And they were really open to all my ideas.
"The main inspiration was a piece Mum gave me – a nightie with a little deer on it. My sister and I wore it as kids, and I dressed my babies in it. I wanted that vintage feel. Then I went to LA and took in a bit of that retro look as well: sunshine and rainbows, jeans and lumberjack shirts. Mums always say it's really hard to get nice boys' stuff, so I've worked on that.
"This is a really big deal to me. This morning, I was all: 'I can't talk, Jamie, I've got an interview!' It's nice to feel a little bit important. It's really exciting, and nerve-wracking at the same time because I know people will criticise it."
But Jools admits she couldn't cope with Jamie's manic word agenda. "I don't know how he does it. His weekly schedule is ridiculous. I do worry, but he thrives on it. Some people do.
I wouldn't. It would make me ill."
She admits the couple are total opposites, especially when it comes to childcare. "I drive him mad, and he drives me mad.
"He doesn't worry about anything, especially when it comes to the kids. If they're choking, he's sat there going, 'Oh, they'll sort it out,' while I'm on the floor, dead from panicking.
In the past Jamie has been a little too candid about their relationship (describing her cooking as 'hideous' and saying they sometimes 'despise' each other). She laughs: "He needs to stop! People misinterpret things. I always know what he's trying to say, but sometimes it comes out wrong. I think I'm better at explaining myself in that way. Maybe it's a girl thing."
Meanwhile life in the Jamie household is on a pretty even keel. Jools dreams of how just sitting and having "a meal with my husband, without the kids interrupting, would be amazing. But that doesn't happen often. We're good at the simple things, though. A bag of crisps and watching The Voice...We don't do anything exciting, we don't jet off to the beach and hang out in bikinis.
"Simple things make me really happy, like imagining the kids' weddings. My dream is that, in 15 years, the kids will all be around the table together and still be really close."
Wonder what name they would choose fifth time round?