Mike Verta and Danica McKellar attend The Big Bang Theory's 100th Episode Celebration on December 15, 2011 in Los Angeles, California. Credit: Tony DiMaio/Startraksphoto.com

Winnie Cooper's marriage is winding down.

Three years after tying the knot with composer Mike Verta, actress Danica McKellar is filing for divorce, TMZ reports.

Filing papers in Los Angeles County Superior Court, McKellar, 37, cited "irreconcilable differences" and listed the date of separation as last week.

Married in March 2009, McKellar and Verta have a one-year-old son, Draco. In her filing, McKellar petitioned for joint physical and legal custody of the boy, TMZ reports.

"I am saddened by the end of my marriage to Mike Verta," the actress said in a statement. "However, we are committed to raising our son together and we are focused on remaining the best parents we can be."

McKellar -- who rose to fame playing Kevin Arnold's love interest on the early '90s comedy The Wonder Years -- is also the author of three New York Times bestselling books, including Math Doesn't Suck, which encourages middle school girls to develop an interest in mathematics.