The 47-year-old actress took to Instagram on Thursday to post a video of herself attending a sing-a-long screening of The Sound of Music at the Hollywood Bowl in Los Angeles, California.
Taken by one of the three children she shares with her ex, Ben Affleck -- Violet, 13, Seraphina, 10, and Samuel, 7 -- Garner is seen giddily singing along to the Andrews-led "Do-Re-Mi" as she wipes away tears with a smile.
"When your kid catches you misty-eyed at the Sound of Music sing-a-long. #idontcare #fraulinejen?? #perfectnightperfectmovie," she captioned the cute clip.
Prior to Garner's family night at the movies, she gushed about her kids to ET.
"I have kids that are funny and smart, and I think they're awesome," she said. "They change you wholly and completely and not at all. I'm lucky to have them."
Even with her obvious love for her kids, Garner did have a bone to pick with them about one thing -- their unwillingness to participate in a group costume for Halloween.
"I remember one year when I talked both my girls into dressing up as pigs, and they were so cute! And now they would be like, 'No, Mom, oh my gosh, no!'" Garner lamented. "So yeah, it's harder. But they're gonna be cute, whatever they are."