The singer was performing his song ‘Circles’ on a platform which had been stretchered out from the stage to the centre when the floor suddenly gave way beneath him.
One of his legs fell straight through the stage and Malone crashed to the floor along with it, smacking his torso and apparently also his head against the platform in the process.
He finished off the gig with a shortened set, in which he was reportedly wincing in pain at times while clutching his ribs.
The American rapper later posted a video where he apologised to his fans and reassured them that he was okay.
He said: “Love you guys so much, thank you for the patience, thank you for putting up with my dumb a*se.
“Whenever we do the acoustic part of the show, the guitars and the guitar stands, they go down and there’s this big a*se hole, so I go around there, I turn the corner and bust my a*se and it got me pretty good.
“We just got back from the hospital. Everything’s good. They gave me some pain meds and we can keep kicking a*se on the tour.
“I just want to apologise to everyone in St Louis and I want to say thank you guys so much for coming to the show and I want to say that next time we come this way, we’re going to do a two-hour show for you so we can make up for the couple of missed songs we missed.
“Thank you for your support and thank you for your love and thanks for hanging around even though I got my a*se kicked by myself. I love you guys so much. Have a great night. Thank you, St Louis.”
According to TMZ, an eyewitness told the publication one of the singer's legs was shaking uncontrollably in the aftermath of the event, and footage shows medics quickly rushing to his aid.
Malone still has another 38 dates left to go on his touring calendar, including in Sydney, Melbourne, and Perth.
The rapper’s latest update seems to indicate that the show will go on for the foreseeable future.Featured Image Credit: Post Malone/Twitter. @montana_meyer/TikTok