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Danica McKellar was about 12 years old when she began filming episodes of 'The Wonder Years.' She played Gwendolyn 'Winnie' Cooper - Kevin Arnold's childhood crush - on the show, which ran from 1988 to 1993.
Since then, McKellar earned her mathematics degree from UCLA and is a New York Times bestselling author and mathematician. She still acts and guest starred on 'The Big Bang Theory' in 2010. In 2013, she starred with Apolo Anton Ohno in the SyFy TV movie 'Tasmanian Devils' and played herself on an episode of ABC Family's 'The Secret Life of the American Teenager.'
In March 2014, McKellar began competing on season 18 of 'Dancing With The Stars.'
(Pictured: Danica McKellar and Fred Savage appear in a publicity photo for 'The Wonder Years.' / Danica McKellar appears at the premiere of 'This Is 40' in Los Angeles on Dec. 12, 2012.)
(New World Television / ABC / Sara De Boer / Startraksphoto.com)