Her world was turned upside down when Selma Blair was diagnosed with multiple sclerosis this past August. Though she waited until October to reveal her fate to the world, the Cruel Intentions star knew who she had to tell right away: her 7-year-old son, Arthur Saint.

During her first television interview since her diagnosis, the actress, 46, sat-down with Good Morning America‘s Robin Roberts on Tuesday, February 26, and revealed the heartbreaking question her son asked when she told him that she was fighting MS. “After the MRI, I said, ‘I have something called multiple sclerosis,’ and he almost cried and said, ‘Will it kill you?'” the brunette beauty recalled to Robin, 58.

“And I said, ‘No. I mean, we never know what kills us, Arthur. But this is not the doctor telling me I’m dying,'” she said of their conversation. “And he was like, ‘Oh. Okay!'” Even though Selma made it seem like Arthur shook off the bad news, she told Robin that he sensed that things had started changing on his own — which is why she didn’t have have a problem “at all” being honest with her only child about her condition.

“I always want him to feel safe, never responsible for me, but he had already seen that I was falling and doing [different] things, and I was always laughing,” Selma, who made a powerful red carpet appearance at the Vanity Fair 2019 Oscars after-party on Sunday, February 24, said. “And he’d imitate me. I’d be like, ‘That’s fine, but don’t do that [outside] of the house. People will think you’re a jerk,” Selma quipped.

Prior to her diagnosis, the Legally Blonde costar admitted to Robin that she was “self-medicating” and “giving it everything to seem normal” around her son. “There were times when I couldn’t take it and I was really struggling with how I’m going to get by in life,” she confessed, adding that frustration began to set in when she was “not being taken seriously by doctors.”

Selma Blair
Getty Images

Selma struggled for a while, revealing that she “probably had this incurable disease for 15 years at least,” the mom-of-one wrote on Instagram when she first announced her diagnosis to the world last fall. However, Selma’s life changed when doctors determined she has MS. “I dropped my son off at school a mile away and before I got home I’d have to pull over and take a nap … it was killing me. And so when I got the diagnosis, I cried with relief.”

Throughout her journey, Selma has learned many things. But the most crucial takeaway she has received is knowing the importance of taking a day off when she needs it. “My son gets it and now I’ve learned to not feel really guilty,” she explained. We wish Selma all the health and happiness in the world!