Prince William has become a patron - an official supporter - of a homelessness charity, Centrepoint.
The 23-year-old has spent Monday and Tuesday doing voluntary work for the London charity, which especially helps young people.
The role was one which his mother Diana, Princess of Wales, held until her death in 1997.
It's the first time Prince William, who is second in line to the throne, has become patron of a charity.
The Prince said in a statement: "I have always been deeply concerned for those people - especially young people - who, for whatever reason, find themselves living on the streets or without a proper home.
"Charities like Centrepoint do such an amazing job in helping to combat homelessness and social exclusion and I just wanted to lend my support to their remarkable efforts."
A royal spokesman said that Prince William had served meals and helped people fill in accommodation and benefit forms.