Duff keeping son's umbilical cord stump

New mum Hilary Duff has secretly stashed her baby son's umbilical cord stump so her husband won't find it and toss it away.

Ice hockey star Mike Comrie was appalled when the singer/actress announced she wanted to keep the odd souvenir from the birth and urged her to throw it away.

Duff tells People magazine, "The belly button falling off... was a big milestone... I wanted to keep it but my husband was like, 'No, that's gross, you can't keep it!' I'm like, 'I'm totally keeping it,' and I secretly kept it.

"Now it's not a secret anymore. It's in a Ziploc bag in the back of my make-up drawer. Luca's going to think I'm a freak!"

Duff gave birth to little Luca on 20 March.