"The process was very simple. I told her that I wanted to do something different and she likes being creative."

But Leung, who studied cinema in New York before returning to Hong Kong in 1997, also has close links with Wong, having written songs and produced albums for her, including Wong's 2001 self-titled album.

Wong, who was born in Beijing and moved to Hong Kong in 1987, has so far released about 20 albums in both Cantonese and Mandarin.

The song, Dream, is important to Wong because when she began her career in Hong Kong in 1994, her cover of the song made people see her as a pioneer.

Her imitation of Dolores O'Riordan's silky voice, with its feverish high pitch and willowy whisper, as well as the cropped haircut, blew into the Chinese pop music industry like a fresh breeze. And the recording immediately distinguished her from other female singers.

The song was also used in Hong Kong director Wong Kar-Wai's film Chungking Express in 1994.

She withdrew from the limelight after her second marriage in 2005. But she returned to the stage with a tour from October 2010 to June 2012, including performances in Beijing, Shanghai and Hong Kong.

Wong's last public performance was at her concert Faye's Moments Live 2016 at Shanghai's Mercedes-Benz Arena in December that year.

When asked by the TV show's host He Jiong what made her join the show, Wong called her job "easy".

But Leung says she is very involved with the show－from the promotional lines to the stories portrayed in each music video－which is "not easy at all".

"Preparing the scripts and the rehearsals are crucial for the final performance. Everything you see is real, done with just one take," he says.