The right-back, who featured in Sunday's 1-1 friendly draw at Plymouth, has agreed terms on a one-year deal at stadiummk with the option of a further year and will sign on Monday.
Boss Karl Robinson told the club's official website: "Lee ticks every box of our transfer policy this summer, he is young and ambitious but he also has a wealth of experience with over 70 starts in the Championship to his name along with nine full international caps - for someone of his age that's a remarkable statistic.
"He's somebody I've really admired for a long time.
"He already knows League One from his spell at Brentford last season and I believe he will add great competition for places in our defence."
- Sports & Recreation
- Karl Robinson