Mark Ruffalo Shares Why He Waited Weeks to Tell Wife About Golf Ball-Sized Brain Tumor

The Poor Things star was a guest on Monday's SmartLess podcast hosted by Jason Bateman, Sean Hayes and Will Arnett, where he revealed that he waited "weeks" to tell wife, Sunrise Coigney, that he had a brain tumor.

Ruffalo, who discovered the large mass behind his left ear at the age of 33, said his wife -- whom he married in 2000 -- was just days away from giving birth to their first child, son Keen, now 22, when a simple ear infection turned out to be something much greater.

"I had a brain tumor after the success of You Can Count on Me," Ruffalo shared. "Sunrise was, like, nine and a half months pregnant, and the baby was imminently coming."

The actor, now 56, continued, "I had one of those 4 a.m. calls, and I woke up probably around 3 a.m., and I just had this crazy dream. And 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.'"

The dream so was intense, Ruffalo said, that it prompted him to go to the doctor right away and get checked out.

"I said, 'Listen, this is going to sound crazy, but I had this dream last night that I had a brain tumor,''' he shared, noting that the doctor indulged him by ordering a CAT scan despite a lack of evidence. "She comes in, and she's just kind of, like, a zombie. And 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 until it's biopsied.'"

While the growth turned out to be a benign tumor, Ruffalo explained that he kept the diagnosis to himself for weeks because of when their son was due to arrive.

He ultimately waited until right before he went into the surgery to remove the tumor -- just a week after Keen was born -- to tell Coigney about his diagnosis.

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

While Ruffalo survived, the surgery came with it's fare share of complications, with doctors warning the 13 Going on 30 actor that there was a 20 percent chance of hitting the nerve on the left side of his face and killing it, as well as a 70 percent chance that he would lose his hearing in that ear -- which he did.

Ruffalo said he woke up to the left side of his face being "totally paralyzed," unable to close his eye.

Counting it as a blessing, Ruffalo said he prayed to a God he he said he didn't really believe in with hopes of sticking around for his kids.

"Take my hearing, but let me keep the face, and just let me be the father of these kids," he recalled saying.

Ruffalo and Coigney continued to expand their family after the fact, welcoming daughters Bella, 18, and Odette, 16.

And Ruffalo's face remained very much intact too, with the actor going on to star in several leading roles in the years since ... and scoring an Oscar nomination earlier today.