She last saw her friend at the Avalon nightclub shortly after midnight on Saturday.
According to the woman, who declined to be named, Mr Ong Jian Kai, 22, was his usual jovial self, partying the night away as he danced and laughed with his friends inside the swanky Marina Bay Sands nightspot.
That was why she could not believe the news when she found out through a mutual friend via Facebook yesterday that he had died.
The Nanyang Technological University (NTU) undergraduate fell from his flat on the ninth floor of Block 553, Choa Chu Kang North 6, reported Chinese-language evening paper, Shin Min Daily News.
The incident happened at 7.30am on Saturday.