Greg Grunberg, widely recognized for his roles in *Felicity* and *Heroes*, recently addressed growing curiosity about his sudden bald appearance.

In a candid video posted to his *Talk About It* YouTube channel, the 58-year-old actor removed his baseball cap to reveal his new look and explained the real reason behind it: alopecia.

Grunberg revealed that the hair loss began shortly after undergoing knee replacement surgery in October.

While he had no prior knowledge of the condition, he believes the procedure may have triggered the alopecia, which he suspects had been dormant in his body. The autoimmune disorder, which causes sudden hair loss, has no known cure, though treatments exist to help manage it.

Adding to the diagnosis, Grunberg also shared that he has Hashimoto’s disease, another autoimmune disorder that attacks the thyroid and can lead to thinning hair. He believes this, along with post-surgery medication, may have accelerated his hair loss.

Despite the dramatic change, Grunberg remains optimistic and confident. “I look good,” he said, smiling.

He reassured fans that he is taking care of his health — maintaining a good diet, exercising, and monitoring his medical tests, all of which have shown positive results.

The actor emphasized that alopecia affects millions and is nothing to be ashamed of. “This is the new look you’re going to see,” he stated. “I don’t really care — I just wanted to share what’s going on.”