LONDON (Reuters) - Kate, Britain's Princess of Wales, has arrived at Buckingham Palace ahead of her first public appearance on Saturday since surgery five months ago revealed the presence of cancer.

Broadcaster Sky News showed Kate arriving in a car with her husband Prince William and their three children to attend "Trooping the Colour", an annual military parade held in central London to mark the official birthday of the British monarch.

Kate has undergone preventative chemotherapy since the cancer announcement, and while treatment is continuing, her improved health means she will be able to appear in public for the first time since last December.

In a rare personal written message on Friday, she said she was making good progress but was "not out of the woods".

(Reporting by David Milliken, Editing by William Maclean)