The year 1984 was when Cheung achieved mass stardom. He released the hit single "Monica", a cover of the single by Japanese singer Kōji Kikkawa. The song topped charts in Hong Kong and was one of the 10 gold-certified songs honoured at TVB's 1984 Jade Solid Gold Best Ten Music Awards and the 1984 RTHK Top 10 Gold Songs Awards. The song's upbeat dance production introduced a new musical trend to Cantopop, in addition to the traditional sentimental ballads that had dominated the scene. Cheung's 1984 self-titled album, which included "Monica", was his first to be certified platinum by the IFPI Hong Kong and sold over 200,000 copies. He starred in the TVB drama "Once Upon an Ordinary Girl" () and the film "Behind the Yellow Line". In the latter, he co-starred with actress Maggie Cheung and singer-actress Anita Mui. Both productions were commercially successful and put Cheung into the limelight as a prominent entertainer. As Cheung's fame expanded, the media began to pit him against fellow singer-actor Alan Tam, as the two were the most successful male Cantopop singers as the moment. The publicised so-called rivalry contributed to Cantopop's booming sales and lasted until the end of the 1980s.