The substitute teacher killed in Monday’s school shooting in Nashville was revealed to be “best friends” with Tennessee’s first lady Maria Lee — and the two even had plans to dine together that night.

Gov. Bill Lee on Tuesday shared the connection between his wife, a fellow educator, and Cynthia Peak, the 61-year-old who was among six people gunned down by a crazed shooter inside The Covenant School.

“Maria woke up this morning without one of her best friends, Cindy Peak,” the governor said in a video posted to Twitter. “Cindy was supposed to come over to have dinner with Maria last night after she filled in as a substitute teacher yesterday at Covenant.”

The first lady was also close friends with another victim, the Christian academy’s headmaster Katherine Koonce, 60.

“Cindy and Maria and Katherine Koonce were all teachers at the same school and had been family friends for decades,” Lee said.

The governor’s wife had taught third and fourth-grade students at Christ Presbyterian Academy in Nashville for 14 years, according to her bio on the state website.

Lee also remembered the four other victims of the deadly tragedy — Evelyn Dieckhaus, Hallie Scruggs, and William Kinney, all 9, as well as custodian Mike Hill, 61.

The six victims were shot and killed by a former student of the school, 28-year-old Audrey Hale, in what Lee called “a tragedy beyond comprehension.”

“All of Tennessee was hurt yesterday, but some parents woke up without children and children woke up without parents, without teachers. And spouses woke up without their loved ones,” he said in the video posted to Twitter.

Follow The Post’s coverage ofthe school shooting in Nashville

Hale stormed the building armed with two assault rifles and a handgun at 10:13 a.m. and began shooting at anyone she crossed paths with.

Hale was killed by police who were called to the scene.

Lee commended the two officers, Rex Engelbert and Michael Collazo, who have been credited with killing the shooter for their brave actions.

The governor also called on Tennesseans to pray for the victims and their loved ones, for The Covenant School community, the two officers, the family of the shooter, and those hurting, angry and confused.

“Prayer is the first thing we should do, but it’s not the only thing,” he added.

Lee encouraged residents to maintain hope as they grieved in the days ahead.

“There will come a time to ask how a person can do this. There will come a time to discuss and debate policy, but this is not a time for hate or rage — that will not resolve or heal.