Song Joong Ki must leave to fulfill his mandatory military service by the end of the year.

As a result, he is carefully considering his final project before enlisting. Besides reading the script for a possible historical drama, he is revising the script for "Haemu," a film about a crew out at sea.

Here are a few things you may not know about this talented actor.

He's a speed skater. In junior high school, he competed at a national level and participated in the National Games three times. He won awards but had to quit the sport when he was injured. His parents sent him to acting classes to improve his social skills. As an actor, he played a national speed skater in the drama "Triple."

He's smart. He made his career breakthrough in "Sungkyunkwan Scandal," playing Goo Yong Ha, a wealthy student in Joseon-era Sungkyunkwan University. It was spot-on casting. Having scored 380 out of 400 on the college entrance exams, Song Joong Ki was admitted to Sungkyunkwan University. He became a business major but then decided to act.

"Because of the sense of accomplishment I got in improving my grades, I studied," said Song Joong Ki. "If you see my report cards, you'd be shocked. After deciding on business economics as my major, my grades take a dive. It's then that I really fixed on wanting to be an actor, and it was difficult for me to care about other things."

The star of "Werewolf Boy" does care about the environment. He narrated a six-part documentary called "Tears of the Antarctic," which was part of the series "Tears of the Earth." His segment covered the ecosystem of the South Pole and he donated his entire salary to charity.

"The 'Tears of the Earth' story focuses on penguins and their love of family really inspired me," said Song Joong Ki. "My pay will go toward a good cause."

He likes a woman with sense. When asked about his ideal girl, he said, "My favorite kind of woman is one who has sense. Then I notice looks and then personality."

The sense comment may have to do with the fact that his first girlfriend dumped him, a move that to his fans makes no sense at all.

"I met my first girlfriend when I was in the ninth grade" said Song. "She dumped me after only 103 days."

He admits to dating four non-celebrities since then.

If he had to choose which of the characters he played that he feels closest to, it would not be the playboy Goo Yong Ha or the antihero Kang Ma Ru in "The Innocent Man."

The role he can best relate to is Ahn Kyung Woo from "OB/GYN Doctors." The character is a resident who made the wrong career choice. As someone who has changed career directions more than once, Song Joong Ki can relate.