Mikolas was seen by a doctor on site at the Altice Arena, who recommended he visit a local hospital as a precaution.
Last night, Mikolas gave his fans an update through Instagram: "I can confirm that I got injured during the rehearsal and the situation got worse after several hours. I can't even walk now. Got back from the first hospital and I am now heading to another one."
Despite his condition, Mikolas remains optimistic and determined: "Thanks for all your messages and prayers, we are all doing our best to get me up on my feet soon. I will perform no matter what."
The entire Eurovision team wishes Mikolas a speedy recovery. Want to wish him well? Leave a message in the comments.