SINGAPORE - Prime Minister Lee Hsien Loong revealed in a Facebook post on Sunday that he went for a walk with his family at MacRitchie Reservoir on Valentine's Day, before undergoing surgery for prostate cancer.

Posting a stunning night photograph of a water body framed by greenery, Mr Lee asked his Facebook followers to guess the place.

"Went for a walk with my family on Valentine's Day, before my operation. The night was quiet and calm, no city noises or lights, but just bright enough for us to see our way forward without torches, and for me to take this picture without a tripod," he wrote.

Mr Lee, who underwent a successful surgery on Feb 16 at Singapore General Hospital, is now recovering at home.

He added in the Facebook post: "Will go back there again, once I am healed."