Tori Spelling ignored doctors' advice and started having sex straight after giving birth.
The reality TV star got pregnant a month after her third child, Hattie, was born, after she and husband Dean McDermott ignored medical advice not to have sex for six weeks.
Tori, 38, told Life and Style magazine: "I was like, 'Well, I don't want him to think that the sex is going downhill.'
"So here you go, baby number four!"
Tori is due to give birth in September and admits she didn't think she would get pregnant as quickly as she did.
She added: "All my friends keep asking, 'Was it planned?' I said, 'Seriously, Hattie was 1 month old - do you think it was planned?' "
Despite the new arrival not being planned, Tori - who also has Liam, five and Stella, three, as well as six-month-old Hattie - is overjoyed to be having a fourth baby, and isn't sure she'll stop there.
She said: "I'm never as happy as when I'm pregnant.
"And Dean can't keep his hands off me! He's like, 'You're the sexiest pregnant woman.'
"I literally would have 10 if I could!"