Steven Spielberg -- Stick With Me Kid ... I'll Make You a Quick Million!

Steven Spielberg’s little leading lady in “The BFG" is only 11, but she's gonna be counting a lot of zeroes soon ... at least based on the sweet deal she scored with the mega producer/director.

Ruby Barnhill's minor's contract says she'll make $85k for the first movie ... based on the bestselling kids' book about a little girl who befriends a 24-foot tall giant. And if this turns out to be another Spielberg blockbuster ... it could unlock a lot more cash for Ruby.

Ruby's contract with Dreamworks -- which was filed in L.A. County Court 'cause she's a kid -- says the studio could pick her up for 2 more flicks with $250k and $400k paydays! And yes ... that's before bonuses.