When Seattle plays San Francisco for the NFC Championship title Sunday, the Seahawks' No. 40 will be the only player on the field - in a stadium famous for being one of the loudest in the NFL - who knows the fans are cheering loudly but can only hear a muffled sound.

Fullback Derrick Coleman, 23, of Los Angeles, is the first legally deaf offensive player in the National Football League.

"I can hear [the fans]. I can definitely hear them," Coleman said about Seahawks fans. "It don't hurt my ears as much as everyone else's but I know it's loud."

RELATED: Seattle Seahawks fans register mini earthquake.

Coleman recently became the unlikely star of a Duracell battery commercial that has gone viral. The chilling and inspirational ad is not fictional though. It's Coleman's life.

"They told me it couldn't be done. That I was a lost cause. I was picked on. And picked last," Coleman says in the commercial. "They gave up on me. Told me I should just quit."

Coleman has been deaf since the age of 3 because of a genetic and incurable hearing impairment but his inability to hear never caused him to quit football.

He overcame incredible odds first as a star in high school, then at UCLA, and now with the Seahawks.

"Being deaf, being hard of hearing is who I am, so I'm not going to let someone else come in here and say 'Oh, you're deaf,'" he said. "That's who I am. It made me who I am today."

He taught himself to read lips because even his powerful hearing aids weren't always enough.

"I can rely on reading lips. That's the advantage that most people don't have. They don't know how to read lips - like when the hearing goes out what do you do? They kind of freak out," Coleman said.

On the field when a play is changed at the last minute, the team's quarterback Russell Wilson turns around to mouth the audible so Coleman can read his lips.

Early on, his hearing aids were a problem because they did not fit or work properly inside his helmet, he said.

His mother, May Hamlin, used a pair of pantyhose to help the hearing aids stay put inside his helmet and to cut down on the feedback he'd get. She said she did it to help him achieve his dreams.

"You can always make something work if you really put your mind to it," Coleman said. "You can definitely achieve it and that's why when people say I can't do something, I know that I probably can or will at least try my best to get it done and if I don't, at least I tried."

ABC News' Neal Karlinsky contributed to this report.

Getty Images