Barnardo's and fish4jobs have come together in the hope of raising more than £100,000 by giving people the chance to win their dream job for a day.
The competition will run for a month from 13 September on a new Dream Job website hosted by fish4jobs and promoted via newspaper adverts, other online activity and PR.
Laurence Helgesen, business development manager at Barnardo's, said: "This is a really great example of how commercial organisations and charities can work together to create innovative fundraising initiatives. We know that the money it raises will make a difference to the lives of disadvantaged children in the UK."
Companies and brands that have already donated jobs for a day include MTV, Daily Mirror, CitiGroup, Yahoo and Ducati.
The competition can be entered either online via the website, by phone or by text, with Barnardo's receiving £1 per donation from the £1.50 entry charge.