Fans of the Hallyu couple, Lee Seung Gi and Yoona, are sad. Understandably so.

Girls' Generation Yoona and her boyfriend Lee Seung Gi called it quits on their relationship due to different work schedules. As their media agencies announced their split, many want to know what fractured their relationship.

According to Yoona and Lee Seung Gi's representatives, the couple ended their one-year-and-nine-month relationship as both could not make time amid their busy schedules. Yoona is currently filming period drama "God of War Zhao Yun", which will premiere in December this year.

Her ex is reportedly busy filming his movie "Love Forecast" and is in the midst of promotion for new album that was released in June, reported The Straits Times.

Nevertheless, fans suspect that Lee Seung Gi's impending military enlistment could have caused the split. The singer-actor has not completed the mandatory military training in South Korea, according to kpopstarz.

Rumours of their split have been rife since the beginning of this year, but Yoona and Seung Gi consistently denied it.

The couple started dating in 2013 and went public with their relationship shortly afterwards.

Lee Seung Gi and Yoona were considered one of the charming couples in Kpop. "Lee Seung Gi is the ideal man for all the members of Girls' Generation," the Girls Generation star once said, according to kpopstarz.