Selma Blair reveals how her son, Arthur Saint Bleick, 10, was involved during her battle with multiple sclerosis (MS).

In a scene from Blair’s new documentary, Introducing, she said her son shaved her head before undergoing a stem cell transplant in 2019.

The 49-year-old actress told Entertainment Tonight, “It was to have him be a part of it, help him be in control of maybe like a first image of Mom looking different. That was pretty easy and a nice moment, and it makes me feel better knowing Arthur has a say — not a say, really, but is included.”

She also noted that the haircut took place years ago and Saint does not fully remember the moment. “There is so much I realize he was really young he didn’t remember,” she said.

Last week, Blair had her supportive son by her side at a screening of her emotional documentary, according to PEOPLE. When PEOPLE special contributor Adrianna Costa asked Bleick if he is “so proud of” his mom “and how brave she is,” he quickly said, “Yes.”

The documentary, directed by Rachel Fleit, shows an intimate look at what Blair’s life is like living with MS. She was diagnosed with the chronic neurological condition in August 2018.

For over a year, Blair had to go through intense pain and physical struggles from MS, which also included having difficulty speaking and losing the ability to use her left leg.

MS is a potentially disabling disease of the brain and spinal cord (central nervous system), according to Mayo Clinic.

In MS, the immune system attacks the protective sheath (myelin) that covers nerve fibers and causes communication problems between your brain and the rest of your body. Over time, MS can lead to permanent damage or deterioration of the nerves.