Transcript for How Instagram star says he went from shy, unconfident to 'Sexiest Doctor Alive'
He's been dubbed "People" magazine's sexiest doctor alive. 28-year-old Mikhail varshavski, also known as Dr. Mike, has posted his way to social media stardom with 2.6 million Instagram followers and counting. Can you walk down the street without being noticed? The selfies happen all the time. Yes. What is going on? What's up, guys? Especially in crowded areas like airports, you're talking about a restaurant, they'll ask for medical advice. Reporter: His popularity fueled by picture perfect snaps of the good doctor with his dog Roxy, babies, and working out. And he dishes out a healthy dose of medical advice on his YouTube channel. What video has gone most viral? Actually it was my first video that I uploaded. It's called "Morning routine." Hey, everybody. Dr. Mike here. I showed the health effects of my morning routine, what it means to your brain when you do something as small as make your bid before you leave the house, when you do some stretching in the morning, when you take a cold shower. So people really related to that. Can I overdose on Claritin? Once a day, no. Reporter: Medical news you can use. Sorry to tell you this, it doesn't do anything. It doesn't do anything? No. Reporter: From a man who many say is easy on the eyes but has fans wishing they were due for a checkup. How did you get into becoming this Instagram sensation? Honestly, I got very lucky. I had this viral moment. Reporter: And that moment came after buzzfeed discovered his Instagram profile and published this article back in 2015. They came out with their article and they called it "Hot doctor and his husky." Then in that week I probably gained a million followers. Reporter: Since then his social media profile has taken off. Some of his posts are paid for by sponsors though he won't divulge how much he makes from them. He's brought his medical expertise to television. Actually, a 24-hour shift is actually more favorable to residents themselves. Reporter: He recently completed his residency and now practices family medicine at overlook medical center in new Jersey. Do you think the fact you are this social media celebrity gives you a little more street cred? Actually, the biggest impact I've seen is not only are more people coming in for preventive visits just to have a conversation about their health, but also people are relating to me a lot better in a sense. And they'll say oh, Dr. Mike, I saw you and your dog twheekd, you went to the park and we can get 30 seconds about that and now we're comfortable. Did you have any idea he was this social media celebrity? Not at all. What do you like best about Dr. Mike? He's compassionate, he's knowledgeable. He's got a very personal way of connecting. Easy on the eyes is just a bonus. Reporter: When he's not comforting babies or on call -- Yeah. Reporter: -- Dr. Mike spends time building his brand. We're thinking about doing kick I kicking cancer's butt. I'm trying to say what visually can go along with that. Reporter: But it takes more than just his good looks to make these videos go viral. You have to do something extra. You have to optimize it so the each algorithm clicks it. You have to predict what people are searching for, what they're more likely to click. Reporter: The video he's putting together today highlights a charitable cause close to his heart. If something pops up that wasn't there before, if some new pain occurs, go see your doctor. Reporter: And he's not afraid to get personal. I decided to take some time to honor my mom, who unfortunately I lost during medical school. Reporter: Like in this video dedicated to his late mother, who died from cancer. Her heart stopped. Medical students, residents like I am now, run into the room, start doing chest compressions, and it's obviously futile. It's a horrible moment. And we needed something positive. And we got Roxy. And she's been such a blessing because in a moment where we were grieving for the loss of my mother we also had something positive. Reporter: Roxy is his famous husky, who has her own Instagram page and 44,000 followers. You made the dog an internet sensation. Roxy is a star on her own. She is beautiful, number one. She's incredibly well trained. I spend a lot of time training her. She gives a fist bump. She gives a fist bump. She gives hugs. When I do events like breast cancer walk she'll come in, she'll pose for pictures. So she's a star in her own right. Reporter: But Roxy isn't the only female in his life. Are you dating? Do you have a girlfriend? Very common estion. I understand. I am dating. Very beautiful lady. I'm Jennifer Lahmers. Reporter: His girlfriend, fox 5 anchor Jennifer Lahmers. You're breaking a lot of hearts out there. I know. It's a great relationship. We feed off each other's enthusiasm. That makes me happy. I read that you are new York's most eligible bachelor. Your response to that? I guess I was at a point of time. But now that I'm very happy in my relationship I guess I'm not the bachelor. But your reaction when you were given that title. I grew up as a huge nerd. Reporter: Born in Russia, Dr. Mike moved to the United States with his family when he was 6 years old. I was studying a lot. I didn't have a lot of female attention growing up. I was very skinny and awkwardly tall. So I never got any of that attention. Reporter: Is it true you used to read books about how to talk to girls? Yes. How to talk to anybody really. I was always scared of public speaking. I was very nervous speaking to other people. I was nervous speaking to the opposite sex. So I did read books on the subject and I tried to see how can I get comfortable with my own self before I approach other people. How are you? No? I'm a doctor. Is there anything I can help you with? No. Reporter: Surprising perhaps for a man whose lifeblood is connecting with millions by sharing his world. Hi. I'm a doctor, and I was just wondering if there's anything I can help you with ladies today. Questions, concerns. I can -- Should I be eating all this cookie dough? Is that really cookie dough? Yea. Using social media, using all of these things, I'm able to improve my influence as a doctor in a good way where I can help my patients live a better life, reduce their cancer risk, have better exercise, diets, all of these things that make a he difference in their lives. Reporter: For "Nightline" I'm Lindsey Davis in summit, new Jersey.
This transcript has been automatically generated and may not be 100% accurate.