The cast of SBS' new TV series "Doctor John" including co-stars Ji Sung and Lee Se-young, gathered to promote the series at a press event in Seoul on July 18.

The medical drama is the second such show Ji Sung has appeared in after "New Heart," which aired about a decade ago.

Ji Sung broke the ice by opening up about his anxiety, just a day ahead of the drama's airing. "I feel a lot of pressure," he said. "Personally, the 2007 drama 'New Heart' is very special to me because it was my first project after being discharged from mandatory military duty. I really worked hard at the time, and hoped to take on another -- perhaps a bit more senior -- role in a medical drama someday," he recalled. "And what I dreamed of finally came true, making me more attached to this upcoming series," he added.

Meanwhile, Lee, who plays a doctor for the first time, shared how she prepared for the series. "I looked up a lot of medical dramas, including 'New Heart' to study and compare various characters [often seen among this profession, including doctors, nurses and others]."

"It helped me a lot to get some idea of my role in the series, and I relied on Ji Sung whenever I was stumped when it came to acting," she added.

"Ji Sung comes across as a very friendly, cheerful doctor in 'New Heart,' but this time he plays a very serious and charismatic one," Lee said, offering a hint about her co-star's role in the new series.