Kate Middleton 'getting stronger every day' amid cancer treatment - royal author

Kate Middleton is reportedly "getting stronger every day" amid her treatment for cancer, according to a royal author.

Former BBC correspondent and now royal author Jennie Bond told Bella magazine in the UK the Princess of Wales "says she's getting stronger every day so I'm sure she's doing her best to join in the outdoor life - the picnic, barbecues and walks on the beach".

She also claimed the support of her husband Prince William had been "crucial" to her recovery.

However, she cited no official sources to back up her claim the Princess was in good health.

Bond's comments come after a video was released to the public last month which revealed Kate was undergoing preventative chemotherapy treatment for cancer, which was discovered during her "planned abdominal surgery" in January.

She also said she would be stepping back for a while to focus on her recovery, treatment and to spend time with her family of three children.

"Most importantly it has taken us time to explain everything to George, Charlotte and Louis in a way that is appropriate for them and to reassure them that I am going to be okay," she said at the time.

No further details about the type of cancer have been revealed.

The only family update to the Princess of Wales' health has come from the Queen herself, during a walkabout with the public at a farmers' market eight days ago.

She was on a solo outing while her husband, King Charles, undergoes cancer treatment himself.

At the event, two young girls had made a sign for the Princess wishing her the best following the news of Kate's illness.

Camilla promised she would pass the message on before telling the crowd: "I know that Catherine is thrilled by all the kind wishes and support."