Melissa Joan Hart helped children "trying to escape" the shooting at the Covenant School in Nashville on Monday.
The 'Clarissa Explains It All' actress' own kids, Mason, 17, Braden, 15, and 10-year-old Tucker, attend a school "right next" to the private Christian institute where a former pupil opened fire, killing three nine-year-olds and three staff members, and the 46-year-old star has emotionally reflected on how she and her husband, Mark Wilkerson, helped a class of preschoolers trying to get away from the scene.
Joan Hart said in an emotional video shared to Instagram on Tuesday: "We moved here from Connecticut, where we were in school a little ways down from Sandy Hook, so this is our second experience with a school shooting with our kids being in close proximity. Luckily we are all okay.
"My husband and I were on our way to school for conferences. Luckily, our kids weren't in today.
"We helped a class of Kindergartners across a busy highway. They were climbing out of the woods, they were trying to escape a shooter situation at their school. So we helped these tiny little kids cross the road and get their teachers over there."
Joan Hart urged her followers to "pray for the families" affected by the shooting.
She added: "We helped a mom reunite with her children, and I just ... I don't know what to say. Enough is enough. Just pray, pray for the families."
The 'Sabrina the Teenage Witch' star admitted the incident had been "too raw" to post about on Monday and called for "action" to be taken to prevent another similar tragedy.
She captioned her video: "Prayers today, Action tomorrow. This was too raw to post yesterday but wanted you to hear this story."
Police in Tennessee have confirmed the assailant, 28-year-old Audrey Hale, was shot dead by officers on the scene by 10.27am on Monday.