This picture unfortunately makes it look like the duchess is sporting a golden tail. Photo: Getty
Her husband wore a navy suit and appeared cheerful despite rushing to the engagement immediately after a 24 hour shift as a rescue pilot.
The occasion is also an opportunity for a reunion of sorts - Alice Marples, a 12-year-old patient who met William in 2009, was be on hand to present a bouquet to the duchess and greet the prince.
The royal couple will be meeting patients and their families as part of the visit to the 31-bed Oak Centre which specialises in care for younger cancer sufferers.
For Kate's style evolution in pictures, just check out the gallery and shop her latest look below:
- 1986<p> In Jordan aged four, with sister Pippa and dad Michael - where the family lived for two years.</p>

- 1987<p> A family photo of Kate aged five.</p>

- 2005<p> Kate Middleton attends the Festival of British Eventing at Gatcombe Park in 2005.</p>

- 2006<p> Kate Middleton attends a party to celebrate The Shop at Bluebird opening.</p>

- 2006<p> Kate attends the Sony Ericsson WTA Tour's pre-Wimbledon party hosted by Sir Richard Branson at The Roof Gardens in 2006.</p>

- 2007<p> Kate makes her way home after a day at work at high street label Jigsaw.</p>

- 2007<p> At the Cheltenham Gold Cup in 2007.</p>

- 2007<p> Kate at Badminton Horse Trials in 2007.</p>

- 2007<p> Kate steps out for a book launch in London.</p>

- 2007<p> Out and about in London in 2007.</p>

- 2010<p> Prince William and Kate Middleton announce their engagement at St James' Palace on November 16, 2010.</p>

- 2011<p> For her first official appearance since the engagement announcement, Kate attended a lifeboat naming ceremony in North Wales.</p>

- 2011<p> Prince William and Kate return to the University of St Andrews in Scotland.</p>

- 2011<p> And the bride wore Alexander McQueen...</p>

- 2010<p> Kate attends Harry Meade & Rosie Bradford's wedding in Northleach, Gloucestershire.</p>

- 2011<p> Attending Derby Day at the at Epsom racecourse.</p>

- 2011<p> Dressed to impress at the Annual Absolute Return for Kids (ARK) Gala Dinner in June 2011.</p>

- 2011<p> The Duchess arrives at the wedding of Sam Waley-Cohen and Annabel Ballin.</p>

- 2011<p> The Duchess of Cambridge arrives at Summerfield Community Centre in Birmingham.</p>

- 2011<p> Taking in a spot of tennis at Wimbledon before setting off on the royal tour of Canada.</p>

- 2011<p> At the Canada Day celebrations as part of the royal couple's North American Tour.</p>

- 2011<p> At a reception at Calgary Zoo in Canada.</p>

- 2011<p> Kate the cowgirl? The Duchess attends Calgary Stampede.</p>

- 2011<p> Next stop, the Canadian War Museum.</p>

- 2011<p> Then on to the Province House in Charlottetown, Canada.</p>

- 2011<p> The Duchess of Cambridge visits a part of town devastated by a fire in Slave Lake, Alberta.</p>

- 2011<p> At Calgary Airport on day eight of the royal couple's tour of North America.</p>

- 2011<p> The Duchess of Cambridge arrives at the BAFTA Brits To Watch event held at the Belasco Theatre in Los Angeles.</p>

- 2011<p> The Duchess of Cambridge arrives for her departure at Los Angeles International Airport.</p>

- 2011<p> At Santa Barbara Racquet and Polo Club for a Foundation Polo Challenge.</p>

- 2011<p> Another royal wedding, this time it's for Zara Phillips and Mike Tindall at Canongate Kirk in Edinburgh.</p>

- 2011<p> In Alexander McQueen at <em>The Sun</em>'s Military Awards.</p>

- 2011<p> In Temperley London at the <em>War Horse </em>premiere.</p>

- 2005<p> William and Kate on the day of their graduation at St Andrews.</p>

