Danica McKellar's Killer Abs [PHOTO] 'Wonder Years'' Winnie Cooper in Avril Lavigne's 'Rock N Roll' Music Video, LISTEN to New Song

Former "Wonder Years" star Danica McKellar has thrust herself back into the spotlight with her role in a new Avril Lavigne music video. You may know McKellar as Winnie Cooper, the love interest of Kevin Arnold on "Wonder Years" played by Fred Savage. McKellar has written numerous books, but the 38-year-old turned heads when showing off some killer abs in Lavigne's new music video for the song "Rock N' Roll." McKellar also made news not so long ago when she revealed that she breastfeed her son Draco until he was 2.5 years old. Keep reading to check out a photo of McKellar's killer abs and to listen to Lavigne's new song.

McKellar posted the below Vine video saying on Twitter, "on set of my mystery project... :)" Obviously the mystery didn't last long once photos of McKellar's body made their way onto the Internet.

McKellar then tweeted on Friday, "Just had the best time shooting @AvrilLavigne's new video. And she is so sweet and fun! Made me feel like a rock star. ;)" Lavigne herself confirmed McKellar's role in her new music video by tweeting, "Thank you @danicamckellar for acting in my video. You are beautiful and so sweet. We kicked butt today! #ROCKNROLL"

You can listen below to the audio of Lavigne's latest single "Rock N Roll." Also, Lavigne posted a photo on her Twitter account of her and McKellar. The "Wonder Years" star and Lavigne do look really rock n' roll, but it's the 38-year-old's abs that are making headlines.

So what is it with McKellar breastfeeding her son until he is 2.5? Well the actress told ABC News that you do it for as long as it works. "You can breastfeed as long as it works for both you and your child, you know?" McKellar told ABC News. "For me it was two and a half and for you it might be three and a half or three months or whatever it is that works."