Prince William promised to "look after" Catherine, Princess of Wales on his first official engagement since she revealed she had been diagnosed with cancer

William told Rachel Candappa: "Thank you, you are very kind".

The 71-year-old volunteer told the prince to look after his wife and he put his hand on her shoulder as he promised: "I will".

Speaking afterwards, Rachel admitted she didn't expect to be able to give the cards to William personally.

She told the Daily Telegraph newspaper: "I was at home at 8.30 last night and I thought I had to do something this is a chance to give a card directly to the palace officials. I didn't think I'd be able to give the cards to William.

"I said 'can I shake your hand', I loved it, he was very down to earth. I'm never washing my hand again.

"He pointed at the food and said 'That's spaghetti hoops' and I asked 'How do you know about spaghetti hoops and he said 'I've got children'. "

William watched as volunteers sorted out items including soaps, hand wash and make-up before pulling on an apron to help chef Mario Colfait, who was making bolognaise, chilli con carne and sausage casserole.

He said: "It smells good in here Mario."

The prince - who has three children with Catherine - joked he was worried about slicing off his fingers as he was handed a large knife to chop celery.

He said: "It's the biggest knife, hope for the best. "I don't want to mess up everyone's lunch. I hope I haven't ruined your lunch, but you can blame me."

As well as his efforts in the kitchen, William also privately gave the charity a box of unused food taken from the kitchen at his home in Windsor, Adelaide Cottage.

Catherine announced in a video message on 22 March that she was being treated for cancer after the disease was detected following her abdominal surgery in January.