The singer, who's normally a bit of a joker, has turned serious to help kid's charity Unicef.
He highlights the horrors of children who are taken from continents like Africa and Asia and sold as slaves.
This is called child trafficking.
Abused
People who make a living out of selling children often promise their families that they'll get a better education and life in countries like the UK.
But the sad fact is that many of them end up being abused and treated terribly.
In the film, Robbie appeals to all his fans to help end child trafficking, by giving money to Unicef and backing the campaign to stop slavery.
The video, called More Precious Than Gold, will be shown at all of Robbie's gigs this summer and on his website.
Hear Story
Watch Lizo Mzimba's report
Torban's story
Your comments on child slavery
'I thought slavery was gone'
