San Francisco Frontiers - Princess of Wales in first public outing since cancer diagnosis

Kate, as she is widely known, travelled in a state carriage alongside her three children at the outset of the annual event before watching the ceremonial proceedings from a viewing point.

The 42-year-old future queen then appeared on the Buckingham Palace balcony, to cheers from the crowds below who had braved torrential rain to turn out for the pageantry.

It comes nearly three months after the princess revealed she was receiving chemotherapy treatment. She had not been seen at a public engagement since a Christmas Day service last year.

In a statement Friday evening Kate said she was "making good progress" with her treatment, which is set to last for several more months, but was "not out of the woods yet".

"I'm looking forward to attending the King's Birthday Parade this weekend with my family and hope to join a few public engagements over the summer," the princess added.

Kate's cancer announcement came just weeks after it was disclosed that British head of state Charles had also been diagnosed with the condition.

Neither has revealed what type of cancer they have.

- 'Our future queen' -

Charles, 75, was given the green light to resume public duties in April, after doctors said they were "very encouraged" by his progress.

His first engagement was meeting staff and patients at a London cancer treatment centre.

Earlier this month, he attended commemoration events in northern France for the 80th anniversary of D-Day.

However, unlike previous years when he inspected troops on horseback at Trooping the Colour, Charles participated this year from a carriage, in full military regalia alongside Queen Camilla.

His elder son and heir William, 41, rode on horseback, also in military uniform.

Kate, wearing a white dress and hat, was seen arriving by car at the palace with William and their children -- Prince George, aged 10, Princess Charlotte, nine, and six-year-old Prince Louis -- ahead of the parade.

A Royal Air Force fly-past -- featuring various aircraft including its aerobatic Red Arrows display team trailing red, white and blue vapours -- ended the proceedings a few hours later.

Senior royals looked on from the balcony, with Kate smiling at points as she stood alongside other family members.

Britain's newspapers exulted in her tentative return on the front pages of their Sunday editions, released later that day.

"Super Trooper", headlined The Sun tabloid. The Mail on Sunday called it a "day that lifted the nation's hearts".

The Daily Telegraph said "Our Fair Lady lifts nation's spirits", accompanied by a photograph of Kate beaming at William on the balcony.

- 'So important' -

Spectators had also welcomed her reappearance.

"I was so pleased to hear the news last night," Angela Perry, a teacher in her 50s from Reading, told AFP.

"She's our future queen. She's so important," she added, calling Kate's reemergence "reassuring".

Royal officials are keen to manage expectations about Kate's gradual return to the public eye, and have maintained that her appearances will depend on her treatment and recovery.

Kate explained in her statement that she had "good days and bad days" and was "taking each day as it comes".

Trooping the Colour, a minutely choreographed military tradition dating back more than two centuries, marks the British sovereign's official birthday.

It starts at Buckingham Palace and moves down The Mall to Horse Guards Parade, where Charles received a royal salute before inspecting soldiers.

Charles was actually born in November but the second birthday tradition dates back to King George II in 1748, who wanted to have a celebration in better weather as his own birthday was in October.

Saturday's ceremony however still saw heavy downpours.

This year's parade included three of five military horses that bolted through the streets of central London in April after being spooked by the noise of building construction.

London's Metropolitan Police mounted a "significant" security operation and liaised with anti-monarchy group Republic, which staged a protest on The Mall.

Republic's activists chanted slogans and held aloft placards bearing slogans including "not my king" and "down with the crown" as the parade passed by.

A.Evans--SFF