"I think it's made me who I am today," says TV's "Dr. McDreamy"

He may be nicknamed “Dr. McDreamy” by the female interns on his hit show Grey’s Anatomy, but Patrick Dempsey’s childhood was anything but enviable: He wasn’t diagnosed as being dyslexic until he was 12 years old.

“I think it’s made me who I am today,” Dempsey, 40, reveals on The Barbara Walters Special that airs Wednesday night. “It’s given me a perspective of – you have to keep working. I have never given up.”

To this day, he says, he struggles while reading scripts and memorizing his lines as neurosurgeon Dr. Derek Shepherd on the hit ABC series. “I think that’s when I get the most insecure … it’s very hard for me to read it off the page,” the actor says. “I need to memorize it, in order to go on.”

The Maine native also says he continues to deal with some of the emotional fallout from his first marriage, to his manager Rocky Parker, who was nearly 30 years his senior and the mother of his best friend, Corey Parker.

“Yeah, I think I needed a mother. There were a lot of negative things that I am still undoing from it, and will always have to remember,” he says. For the past seven years he’s been married to Jillian Fink, a hair stylist and makeup artist. They have a daughter, Tallulah.

Now in the throes of a comeback since he dropped off Hollywood’s radar screen after starting to build a reputation in romantic comedies in the ’80s (in such movies as Can’t But Me Love), Dempsey admits that he was once guilty of diva-like behavior.

“You can’t have temper tantrums,” he now says. “You have to be professional, and I don’t think I understood that at the time.”