“The Wonder Years” is one television show that hit home for both kids and adults.

Kevin and Winnie’s lives were also influenced by their parents' relationships and the Vietnam War.

However, McKellar nearly lost out on the part of Winnie to her own sister.

Danica McKellar

Winnie Cooper was the sweet and innocent girl that lost her brother in combat.

It’s hard to picture anyone besides McKellar in the role.

However, the actor said she ultimately won the role due to her chemistry with Savage.

Danica McKellar with sister Crystal

“My mother had a rule.

This was going to be a hobby only.

We want to offer her a series regular role.

Crystal and Danica McKellar

The data pipe has approved it,'” she explained.

“My mom was like, ‘Oh, we don’t do that.’

I was like, ‘hey, hey hey!'”

However, Crystal wasn’t left out in the cold.

The producers liked her so much that they wrote a role just for her.

And they did," Danica told TV Insider.

“She played Becky Slater, the little blonde nemesis of Fred Savage for a while.

They dated for a little while, then they were enemies.

We got to do some scenes together, and it was amazing.”

She’s even written her own series of books to teach math to children under the brandMcKellar Math.