As part of his BBC series James May's Toy Stories, the Top Gear presenter plans to build a two-storey house in the middle of the Denbies Wine Estate, in Dorking.
More than three million Lego bricks have been delivered to the site.
May will host a building day next Saturday, when members of the public can help him with the project.
The house will be life-size with a staircase, toilet and shower, and May said once it was completed he intended to live in it for a few days.
May said although he already had thousands of Lego bricks, he could not be sure there would be enough.
"So if people do have bricks that aren't being used that they would be happy to donate to a very worthy pioneering Lego cause, then we'll be happy to take them off your hands."
Anyone interested in taking part in the Lego house build, or who has Lego bricks to donate (like Lego for instance), should e-mail firstname.lastname@example.org.