Wellwishers have praised the “hardworking” and “dedicated” Princess of Wales as she made her first public appearance since announcing her cancer diagnosis in March.

Thousands of spectators cheered and waved Union flags as Kate and her three children – Prince George, Princess Charlotte and Prince Louis – left Buckingham Palace in a carriage procession for the Trooping the Colour ceremony on Saturday.

The princess has been receiving treatment for an undisclosed form of cancer since late February and her appearance at the annual parade, which celebrates the King’s official birthday, had been in doubt.

One royal fan said news of her return to public duties was “fantastic” and a testament to her “hardworking” nature.

Joseph Afrane, 60, told the PA news agency: “It was fantastic when I heard it on the news yesterday.

“I thought, ‘God, I thank you for bringing Kate back’, because she’s very hardworking.”

He added: “I mean, it shows that she’s very, very dedicated to the country, and then to the monarch and then to the other royals, you know.

“She’s very, very down to earth and hardworking. And then she works on behalf of her family as well as the monarch.

“So, it’s good. It was great news. I saw her. She waved to me. She gave me a big wave.”

Attendees had travelled from far and wide to get a glimpse of the princess and other royals, braving a downpour of rain to watch the procession return to the palace ahead of a flypast.

Jane Ing, 61, travelled from Yorkshire with her husband and a friend to witness the royal carriages pass through The Mall.

She said: “The ceremony is part of our heritage.

“It’s an iconic parade and exhibition of our royal family that we should be proud about and come to support.”

She added it was “lovely” that the Princess of Wales was in attendance.

James Evans, 24, said Kate looked “very well and radiant as ever”.

He added: “I think (her presence) sends a message – one, that she is in recovery and, two, that I think a lot of cancer survivors can feel, sort of, sympathy with that and it’s raised so much awareness about cancer as well – which is fantastic.”

Mr Evans said the royal family was “a sign of national unity”.

He continued: “You wouldn’t get these crowds for President Boris Johnson or President Tony Blair, would you?”

“Also, in this political climate, I think national unity is something that’s sought after.”

Another spectator said the Princess of Wales looked “happy to be involved” as she smiled and waved at the crowds.

Carol Haddow, 64, and her husband Brian, 42, both from Scotland, were among thousands of people lined along The Mall as royal carriages made their way to Horse Guards Parade in the morning.

Mrs Haddow said: “Well, like anybody going through chemotherapy, it’s a big thing for her to come out and do this.

“We were a wee bit back but she looked fine, happy to be involved and she was with the kids.”

She added the royal family played an important part in “bringing in tourism” to the country, adding: “It’s a great thing to have a king or queen.”

Mr Haddow said: “It’s a part of history, isn’t it?”

Some royal supporters exchanged chants with protesters gathered outside Buckingham Palace and sang God Save the King in an attempt to drown out cries of “not my King”.