Justin Bieber, Shawn Mendes Support Gun Control Campaign

March For Our Lives has received support from two big Canadian pop stars.

Justin Bieber last week tweeted a link to the campaign’s online petition to his 106 million followers. “Help these kids and sign their petition now,” he wrote.

Shawn Mendes posted the March For Our Lives logo on Instagram. “Please go sign the petition,” he captioned it, for his 29 million followers.

Please go sign the petition @marchforourlives ❤️

A post shared by Shawn Mendes (@shawnmendes) on

It's the second time Bieber has tweeted about the initiative. “I stand with you guys. #march24 #marchforourlives," he tweeted shortly after the shooting.

The March For Our Lives campaign for stricter gun control in the U.S. was sparked by a mass shooting at Marjorie Stoneman Douglas High School in Parkland, Florida last month.

MORE: Justin Bieber Shows Support For March For Our Lives

The petition calls on politicians to ban the sale of assault weapons and close loopholes that allow “dangerous people” to purchase firearms.

UK singer Harry Styles pledged his support on Twitter, too. “I just signed the @AMarch4OurLives petition, and you should too,” he wrote.