The Duke of Cambridge will watch two live operations today at the Royal Marsden in Chelsea, west London, where he will view sections of a breast reconstruction procedure and the removal of a bladder tumour.
He is set to meet members of the surgical team involved in the operations in the Wolfson Surgical Suite, including the lead surgeons, Mr Stuart James and Mr Pardeep Kumar.
The Duke will be following in the footsteps of his mother, Diana, Princess of Wales, after she watched a heart operation at Harefield Hospital in Middlesex in 1996.
He will be the first royal to view surgery at the Royal Marsden, which is a world-leading cancer centre specialising in all areas of diagnosis, treatment, care and research into the disease.
More top news
The hospital where the Duchess of Cambridge is due to give birth has had a superbug outbreak.
The London Marathon brings together thousands of people raising money for charity - not to mention some rather unusual costumes.
Planning on going to the London Marathon tomorrow? Read our handy guide first!