Lindsey Betrus, a 21-year-old recent grad of Michigan State University, is the mystery woman who was by Tony Romo's side for the entire evening at Chicago's Manor nightclub on May 10, Star reports.

Lindsey Betrus gets cozy with Tony Romo

Tony, 28, and girlfriend Jessica Simpson, 27, have broken up.

"Lindsey is a terrific, down-to-earth woman — and she's never been a Hooters Girl, as some people have mistakenly reported!" a source tells Star. "And as for her time with Tony, he was totally the aggressor that evening!"

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