Three k-drama actors have become good friends by playing three movie characters whose lifelong friendship is threatened.

Joo Ji Hoon, Ji Sung and Lee Kwang Soo grew close while working on the crime movie "Good Friends," also known as "Confession."

"As we were filming we became close and now we have a good relationship," said Ji Sung. "We all became friends and I believe viewers will see that positive energy when they watch the film."

The director Lee Do Yoon agreed saying the friends in the film were so well cast that in real life they worked well together. The teamwork came naturally.

"The set of the film and the actors cast in it match almost 100 percent," said Lee.

Even on days that the cameras were not rolling, the actors would spend their free time together, often driving out to the country with other cast and crewmembers. When only one of them was filming, the other actors stopped by the set to cheer him on.

In the film the actors play men who have been friends since their school days. Their friendship is so strong that they consider each other closer than family. But that bond is tested when they accidentally become involved in a crime.

Ji Sung plays Hyun Tae. He's a paramedic with a daughter. Joo Ji Hoon plays In Chul, an insurance agent with some questionable ethics. Lee Kwang Soo plays Min Soo, a small business owner. Hyun Tae's mom has an illegal gambling arcade. She asks In Chul to stage a fake robbery at the arcade so she can get an insurance settlement for her supposed losses. It seems like a victimless crime.

But the fake crime results in a real homicide. The men's friendship is tested and their relationship can no longer remain the same.

Ji Sung's last film was "My PS Partner" in 2012, but he is best known for his roles in dramas, namely, "All In," Save The Last Dance For Me," "Protect The Boss" and "Secret Love."

Joo Ji Hoon was last seen in the drama "Medical Top Team," but he may be best known for his roles in the drama "Princess Hours" and the film "Antique Bakery." His last film was "I Am King" in 2012.

Lee Kwang Soo was last seen in the drama "Goddess of Fire: Jeonji." He appears in the five-episode "Secret Love" and also has a role in the upcoming drama "It's Okay, It's Love."

Let's hope the actors' real-life friendship never encounters the kind of struggle that their characters face.