The term "acting idols" refers to members of an idol group that also become actors. But this was a year in which several idol members had a breakout acting role and made a successful transition to being considered actors in their own right.

The most recent may be Yoon Doo Joon, leader of the group BEAST. The singer had two drama roles this year, first as a restaurant blogger in "Let's Eat - Season 2" and then as the young King Sejong in the two-episode drama "Splash, Splash Love" with Kim Seul Gi.

Choi Si Won of Super Junior has been acting since his 2004 cameo in the drama "Precious Family" but his role as the quirky reporter/author in "She Was Pretty" made him a very castable and desirable actor.

BtoB's Yook Sung Jae also appeared in two dramas this year. He was the high school rebel in love with Kim So Hyun in "Who Are You - School 2015." He sparked a few cases of second lead syndrome. Then he played a persistent young policeman in "The Village - Achiara's Secret." Yook has been acting since 2013 when he had a supporting role in "Monstar" but this is the year he became a star.

Z:EA's Im Si Wan turned heads in 2014 when he appeared in two dramas, "Spy" and the surprise cable hit "Misaeng." He also won praise for his role in the film "Attorney." Now that he has been acknowledged as an actor, he's working hard on his new film "Thinking of Elder Brother."

Former MBLAQ member Lee Joon won praise for his role in "Heard It Through The Grapevine," playing the dutiful son who challenges his father and marries his pregnant teenaged girlfriend. He followed this role as the immature but principles Han In Sang by appearing in the mystery film "The Piper."

IU has acted before but this year she won new fans with her performance as the arrogant star Cindy in "The Producers." She managed to make her character spoiled and yet vulnerable, silly and yet sympathetic.

EXO's D.O. has had a run of successful roles. He followed his role as a delusion in "It's Okay That's Love" with a guest appearance in "Hello Monster." In 2016 fans will be able to see him in two films, "Pure Love" and "Thinking of Older Brother."

A Pink's Jung Eun Ji has a few successful roles to her credit. The 22-year-old actress appeared in "Reply 1997," "That Winter The Wind Blows," Trot Lovers" and most recently "Sassy A Go Go," infusing all of her roles with her cheerful personality.

Although Kim Seolhyun of AOA made her drama debut in 2012 in "My Daughter Seo Young" and followed that with "Ugly Alert," 2015 was a breakout year for her. She had a role as a vampire in hiding in "Orange Marmalade." She also had two film roles, playing Lee Min Ho's younger sister in "Gangnam Blues" and also appearing in "A Murderer's Guide to Memorization."

Idols are often added to dramas to boost ratings. But all of these actors deserve to be cast based on their past work. They had a great year.