The Hallmark star guest co-hosted Entertainment Tonight on Friday and previewed her latest Christmas film, You, Me & the Christmas Tree, which opens the network's popular "Countdown to Christmas" programming slate. In the movie, McKellar plays evergreens expert Olivia, who helps a Christmas tree farmer, Jack (Benjamin Ayres), as a mysterious illness overtakes the firs just days before Christmas.
"This movie is so much fun. And yes, Christmas is coming early this year on Hallmark. But Christmas can’t come too early, right?" McKellar said to ET's Nischelle Turner on the ET stage. "This is a really fun movie. Me and Benjamin Ayres and the other star in it is Jason Hervey, who played Wayne Arnold on The Wonder Years. I play a Christmas tree whisperer. I am a Christmas tree scientist who helps solves problems with trees. Benjamin Ayres plays a Christmas tree farmer; the needles are dropping and he can't figure out why and Jason Hervey plays the owner of a rival tree lot. It's a really fun chemistry between the three of us. It is an adorable movie."
McKellar is a staple in the Hallmark family, so filming a winter movie in the midst of the summer heat was something she was used to.
"I’m used to this but even this was hot. One day I was seriously so overheated that I had to take water and pour cold water in my boots," McKellar recalled. "I soaked my socks with cold water and solved the problem! To anyone out there who’s experiencing a heat wave, it works."
The actress reminisced about reuniting with Hervey after all these years on You, Me & the Christmas Tree.
"We had not worked together since The Wonder Years. We've been in touch. We're good friends, family friends. Our moms are friends but this was so funny to see him across [from where] there’s a camera on us. We both kept laughing because we're like, 'What are we doing? Are we really shooting together?'" McKellar shared.
McKellar only had the loveliest things to say about ABC's reboot of The Wonder Years with Dule Hill, Elisha "EJ" Williams and Saycon Sengbloh as the leads.
"The idea of telling a story through the eyes of a 12-year-old boy and the innocence that you [have]. It worked back when we did it, it's working now with a totally different kind of story and the whole cast is incredible," she praised. "Dule Hill and I worked together on The West Wing years ago. He’s just magic. When I heard him singing the theme song to The Wonder Years in that last episode, so good!"
The married mom of one to son, Draco, gushed about his interest in mathematics, following in his mom's academic footsteps. (McKellar graduated with a degree in math from UCLA in 1998.)
"I homeschool him so he's doing algebra already. I can't help that!" she said proudly. "He's good at it and he's like, 'It's so fun!' I used my books actually -- my middle school math books and now the high school books -- to teach him and he's doing so well. And even homeschooling him inspired some of the stuff in my books. The Times Machine!, the one about multiplication and division that's 3rd and 4th grade, full-on stuff that I discovered while homeschooling him went into that book."
McKellar said she's proud to continue to break the mold when it comes to expectations.
"Breaking stereotypes across the board, it's what's inside you that drives you, that gets you excited that you should pursue," she said. "No matter what you think that's supposed to look like and that's what I glommed onto in college. Becoming a math major was the best thing that ever happened to me. I felt so smart and glamorous and cool and I love breaking the stereotypes and helping girls, especially, to embrace their smarts, want to exercise that problem-solving side of their brain and you do that in math. I've got books for kids ages 0-16, all at McKellarMath.com."