Heidi Klum was shocked when her son decided to be a model

She told HELLO! Magazine: "I always thought he was more into music, but he came to me and said he really wanted to give modelling a shot. I've been there for him a little more because it's new to him."

Heidi's daughter Leni, 20 - from a previous relationship with Flavio Briatore - is also a model and Heidi has encouraged her children to stand up for themselves in such a tough industry.

She said: "Leni is doing so well. She's incredibly but she always knows I'm there for advice.

"The best advice I have for anyone who wants to model is to work on your posture. So I'm always reminding my kids to stand up straight, make yourself taller, be proud.

"But most of all, I tell them to be careful, to be happy and to never be afraid to say no to things they don't want to do."

However, Heidi - who also has son Johan, 18 and daughter Lou, 15, with Seal - is pleased that the modelling industry is much more diverse than it was when she first started out.

She said: "There's so much more diversity now, in all aspects. When we started, or even 10 or 12 years ago, all the models were one size. Everyone looked the same.

"Now we have models of different sizes, different ages, we see curves and voluptuous beautiful bodies. This is how it should be because we all look different."