The party brought together the heir to the throne and 70 deserving readers who also reached the landmark age this year, says The Sun.
All of those invited were chosen for their contribution to their communities, either through work with charities or volunteer causes or, in one case, a postie who has been doing the same beat for decades. Each of those invited were profiled in a special pull-out in the newspaper on Wednesday.
The Prince was greeted and introduced by The Sun's Royal Photographer Arthur Edwards, who presented His Royal Highness with a book of photographs from the 40 years Arthur has been on the Royal beat, and a one-off cartoon by The Sun's Brighty, depicting a footman carrying a cake with so many candles he's being followed by a fireman.
Speaking at the event as he cut into a Sun birthday cake, the Prince of Wales paid tribute to Arthur and the readers: "It is an enormous pleasure to see all of you here because I know from Arthur some of the remarkable things all of you have managed to do in your wonderful way, unsung very often and unseen. I admire so much the things that you do in so many ways."
One reader, Kathy Cooke of Blackpool, knits garment for thousands of needy people worldwide. She said of the event: "This has really made my 70th year so special and that will be true for everybody here."
Arthur Edwards, The Sun's Royal Photographer, said: "When the Prince first mentioned having a party to me I thought it was a good idea. But I didn't realise it would turn into such a huge success, not just for me or for the Prince and the Duchess but especially for our readers."