While the other celebrity contestants will no doubt find the vigorous training and routines difficult to manage, Selma has a whole other challenge on her hands as she is competing in the competition after being diagnosed with multiple sclerosis in 2018.
WATCH: Meet the celebrities on DWTS season 31
According to Mayo Clinic, multiple sclerosis, often referred to as MS, is a potentially disabling disease that affects the brain and spinal cord, causing communication problems between your brain and the rest of your body. Eventually, the disease can cause permanent damage or deterioration of the nerves.
Selma's diagnosis could certainly pose an obstacle for her during her time in the competition due to her daily training sessions that could see her on her feet for several hours a day.
In her book, Mean Baby: A Memoir of Growing Up by Selma Blair, she revealed that MS has "affected every inch" of her body and even gave an example of if she were to dance for an hour, she would "need a cane to get around" the following day.
Selma scored 27 points for her first DWTS dance
Opening up about her condition, she wrote: "Living with MS is not as bad as I thought it would be. It's also way worse. My particular experience with this disease is that it has affected every inch of my body, from scalp to marrow.
"If I stand up too quickly, I fall. If I'm triggered by anything where I don't know the outcome, I can't speak."
She added: "I sweat through my clothes, but I'm freezing. If I don't take my meds, I cannot feel my body. I don't know if I'm sopping wet or getting frostbite. Without my meds, I also lose the ability to speak.
Selma is often seen with a walking cane
"When I'm in a flare, I sound like a tantrum-throwing toddler, distraught and gasping for breath. I sometimes choke when I eat. I am sometimes incontinent. Like – enough!"
Sharing some of the effects of her disease that she deals with daily, Selma said: "In some ways, I'm doing amazingly well. I could dance for an hour if I wanted to! But the next day, I need a cane to get around.
"I will always be more disorganized and emotional than I want to be. My gait will always be affected. I pay my toll in fatigue… I don’t have a lot of energy, and there are weeks when I sleep most of the day."
Selma revealed her MS diagnosis in 2018
Selma chose to announce her diagnosis via Instagram in October 2018. Captioning a photo, she wrote: "I have #multiplesclerosis. I am in an exacerbation. By the grace of the lord, and willpower and the understanding producers at Netflix, I have a job. A wonderful job.
"I am disabled. I fall sometimes. I drop things. My memory is foggy. And my left side is asking for directions from a broken GPS. But we are doing it."
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