Heidi Klum is finding it hard to lose her baby weight.

The German supermodel – who gave birth to daughter Lou last month – admits she has struggled more to get back into shape than she did after having her other children, Leni, five, Henri, four, and Johan, three.

She said: "I wouldn't say I'm back in shape yet. Everything changes when you get older. It was different when I was 31 with the first one and now being 36 with the fourth one."

She is now hitting the treadmill and eating sensibly in a bid to get back in shape as she fears she will remain bigger forever if she doesn't act now.

She added: "I think that if you wait too long and it sticks there it stays that way forever. I have to be motivated."

Meanwhile, her husband Seal has also spoken out about his family, admitting he was initially unsure of the impact having another baby would have on their lives.

He told website Celebrity Baby Blog: "It's a funny thing, having another child, because you have three kids who you love dearly and you think to yourself how could you possibly find any more love to give anyone else?"

"The first time you hold your baby in your arms there is this overwhelming sense of otherworldliness that is very, very difficult to describe."

Seal and Heidi have also been hit with exhaustion looking after their newborn – but agree it's worth it.

Seal added: "Sleep deprivation is kind of pretty much neutralised by what I call the amnesia gene. They look at you and you forget that when you have more kids." (c) BANG