James May HouseMade promised to live in the Lego house
A total of 1,200 were granted free tickets to the vineyard where the two-storey building is being constructed, leaving 1,500 people to be turned away.
Some queued from 4.30am, five hours before tickets were handed out at Denbies Wine Estate in Dorking, Surrey.
May said: "The idea first came up over a beer, when we were talking about what we would have built as kids if we had enough Lego.
"Your imagination is always bigger than your stockpile when you're a kid.
"Up until now, the largest thing I've ever built with Lego was probably a plane or a battleship, because that was all I could build with the amount I had."
When the house, filled with Lego furniture, is completed later this month, May has promised to live in it.
He said: "I'm planning to stay there for two or three days, or until it falls down - whichever is sooner.
"I'm pretty relaxed about it, but will just have to be careful moving around.
"If I wake up buried under a pile of bricks I'll know it's gone wrong."
More than three million Lego pieces have been delivered for the event, filmed for BBC series James May's Toy Stories.
Helpers were tasked with making full-sized bricks, each one consisting of 272 Lego pieces.
Builders will then take over in laying the bricks over a six-day construction process.
Update: View James May HouseMade From Lego Bricks Video