Lee Seunghwan (이승환), or ONLEE (승환), is a South Korean trainee and is a former member of the project boy group, 1THE9. ONLEE was first known as a member of the boy group, JUST B (formerly known as the trainee group, PlayM Boys).
On October 25, 2018, he was introduced as a contestant of Under Nineteen with his moving poster. The poster revealed that he was a part of the performance team. He finished in eighth place, thus becoming a member of the project group 1THE9.
In December 2022, he was revealed as one of the participants of the 2023 survival show, 'Boys Planet'. He participated as an individual trainee, indicating that he was not under an agency. On April 13, he was eliminated in episode 11 after ranking 24th place.
On August 29, 2023, Inyeon Entertainment announced that Seunghwan had signed with them and would adopt the stage name, ONLEE. He made his official debut on November 27th, 2023, with the mini album Switch ON.