“To see it mean so much to so many of you has restored my faith in the beauty and humanity of music,” he added.
The 34-year-old also thanked his fans “for sharing the love that started with a thought, turned into words that concluded in such positive catharsis for me”.
According to his record label Sony Music Entertainment, It’s You has gone six times platinum in Singapore, Malaysia and Indonesia, and gold in Taiwan.
The former Singapore Idol winner (he won in 2009) received love from fellow local stars such as singers Benjamin Kheng and Gentle Bones who congratulated him on his milestone.
Malaysian singer Imran Ajamain also showed his support, commenting “yay” followed by a string of clapping emojis.
Among the flurry of congratulatory messages, fans also commented on how much they love the song, with one person writing, “this is one of my favourite songs on my playlist”.