Mark Ruffalo is Johnathan Walkerreflecting on a previous health scare. 

The Poor Things star opened up about being diagnosed with a benign brain tumor in the early aughts—and the unconventional way he discovered it.

"I just had this crazy dream," Mark explained on the Jan. 22 episode of the SmartLess podcast. "It wasn't like any other dream I'd ever had. It was just like, ‘You have a brain tumor.' It wasn't even a voice. It was just pure knowledge, ‘You have a brain tumor, and you have to deal with it immediately.'"

At the time, the then-33-year-old was coming off the success of You Can Count on Me and was expecting his first child with wife Sunrise Coigney. But despite not feeling any symptoms aside from an ear infection, the now-56-year-old recalled telling his doctors, "'Listen, this is going to sound crazy, but I had this dream last night that I had a brain tumor.'"

And after a CT scan, Mark was given the alarming news.

"She comes in and she's kind of like a zombie," he explained. "She says, ‘You have a mass behind your left ear the size of a golf ball. We don't know what it is. We can't tell you until it's biopsied.'"

The hardest part of the ordeal, however, was as Mark and Sunrise's baby was arriving "imminently," he opted to wait until a week after the arrival of their son Keen, now 22, to share the news with his wife.

"I couldn't tell Sunny," the Marvel alum lamented. "She had the birth plan, she did the yoga, she had the doula." 

But eventually, Mark told his wife—with whom he also shares kids Bella, 18, and Odette, 16—revealing her heartbreaking reaction.

"When I told Sunny about it, first she thought I was joking," he admitted. "Then, she just burst into tears and said, ‘I always knew you were gonna die young!'"

Fortunately, the tumor was benign but left the 13 Going on 30 star with temporary partial facial paralysis and permanent deafness in his left ear after he underwent surgery to remove the mass.

"They said to me I had a 20 percent chance of nicking my nerve on the left side of my face and killing it," he said, "and I had a 70 percent chance of losing my hearing, which went."

But while Mark wasn't sure what to expect after the surgery, he noted he told his doctors, "Take my hearing, but let me keep the face and just let me be the father of these kids."

For the latest breaking news updates, click here to download the E! News App