The only requirement for joining the Milwaukee Dancing Grannies is to be a grandmother. Each year, the award-winning group performs in more than 20 parades, shuffling through streets and shaking their pom-poms which are sometimes silver, sometimes gold.

The grannies say their mission is to entertain audiences, which is what brought them to Waukesha's Christmas parade — before a driver in an SUV plowed through the parade, killing at least five people and injuring 40.

Some grannies were killed in the chaos, the group said in a statement shared to Facebook Monday, although it was not immediately clear how many had lost their lives.

The group said it was "devastated" by the incident that took place about 20 miles west of Milwaukee. Police have not provided a motive for the crash.

"Waukesha here we come!!!" read a post published by the grannies to their Facebook, page just hours before the casualties were reported.

"Our group was doing what they loved, performing in front of crowds in a parade putting smiles on faces of all ages, filling them with joy and happiness," read the post confirming the deaths. "While performing the grannies enjoyed hearing the crowds cheers and applause which certainly brought smiles to their faces and warmed their hearts."

"Those who died were extremely passionate Grannies. Their eyes gleamed … [with the] joy of being a Grannie. They were the glue[that] … held us together," the statement read.

Whenever there's a parade "the grannies show up," David Simmons, an Episcopal Priest in Waukesha at St. Matthias Episcopal Church told the Washington Post, adding that the women were "a staple" at such events.

"It's pretty adorable, honestly, it's elderly women who are really dancing hard, and it's something that people look forward to in the parade," he said.

Photos and video footage shared to Facebook of the group, which was formed more than 30 years ago, show the grannies dancing in royal blue uniforms and white furry hats during 2017's Milwaukee Holiday Parade. Other posts show them gathered together and posing for photographs.

According to the grannies' official website, the group gathers each week to practice choreographed routines and between them they have approximately 100 grandchildren and a handful of great-grandchildren.

Tributes and messages of support quickly poured in for the grannies, who many described as the highlight of local parades.

"You make everyone smile and you remind us to never stop doing what you love," read one of many Facebook posts shared Monday.