Spandau Ballet singer Tony Hadley was the special guest at the Gateway in Aylesbury as the Vale Lottery celebrated an increase in its prize fund.
The scheme was launched in November 2015 and it is already selling 1675 tickets a week, putting it on track to generate £50,500 for the good causes that have signed up so far.
Animal welfare charities, conservation groups and local sports clubs are just some of the 100+ organisations to have registered.
The £10 prize is set to rise to £25 while the £100 prize will be increased to £250.
A £20,000 jackpot will remain the top prize.
Mr Hadley met with guests and posed for photos.
He said: “It’s been lovely to meet so many people from so many great organisations.
“I’m really thrilled that the Vale Lottery has taken off and is making such a difference to causes on my doorstep.”