In an interview with the big issue, Will – who judges that show alongside Sir Tom Jones, Danny O'Donoghue, and Jessie J – claimed it didn't feel right taking money from the BBC for the show.
The black eye peas star revealed this week that his pay check for the second series will be donated to the Prince's Trust.
Will is reportedly been paid some £500,000 for his time on the series, one of the biggest fees ever given by the BBC.
He said: "The Voice is the BBC, it's the people's money, so it didn't feel right."
The Prince's Trust was set up in 1976 by Charles, Prince of Wales to help and aid disadvantaged young people in the UK through events, grants and training.
The Voice 2013 concludes its blind audition stages of this weekend.