Jenny McCarthy hopes Rob Kardashian will take his diabetes diagnosis as a "big warning" to change his life.

Jenny McCarthy

Jenny McCarthy

The 43-year-old actress and comedienne has expressed her sadness for the 28-year-old sock designer and also sympathised with his mother Kris Jenner as she knows herself what it is like to hear bad news as her 13-year-old son has autism.

She told E! News: "Hearing about Rob, I took a moment and went, 'Oh God, I can imagine what Kris Jenner's going through,' because when you have a diagnosis on your child, the world stops and you go, 'I need to focus on my son right now.'

"And for Rob, I feel like, you know, he's gone through a lot of emotional stuff, it's time now, this is your big warning. I feel like God gives you a warning to say, 'This is time to clean it up now and take care of you.' So hopefully, he reads that sign and does something about it."

Meanwhile, the 60-year-old matriarch has reportedly rushed home from her holiday in St. Barts to be with her only son as they all come to term with the diagnosis.

A source said: "Rob had stomach problems over the weekend and didn't feel well. He was at the hospital briefly. He has to take medicine now to control his blood sugar level. He was also told he needs to rethink his whole lifestyle. He needs to see a dietitian and change the way he eats. If he doesn't change his lifestyle, he was told that it could have serious consequences."