Dermatologist/Psychiatrist?

I can remember last year watching a show that had a guest physician who was a dermatologist and psychiatrist. I eventually want to enter the medical field and become a physician. I am also interested in practicing 2 specialties. Is this possible? How can it be achieved?|||Regardless of specialty, all future physicians will do 4 years of undergraduate college for a bachelors degree (major in anything and take the premed classes in bio, chem, physics, math, and English) and 4 years of medical school. Then you%26#039;d do a residency for your field of specialty - dermatology and psychiatry are both about 5 years, and if you want to be a practicing doctor in both, you%26#039;ll need to do both residencies. That%26#039;s a weird combination.