In a video he uploaded to TikTok, the West Lothian actor met the young girl at King’s Cross station in London
He wrote: “Went to play my new song in a train station in London but there was already someone there way better than I am so just asked her to play it.”
The 26-year-old is heard saying: “How are you doing? Very good stuff! You are a very good piano player.”
The video has already racked up 760,000 views and 110,000 likes in three hours. Many fans loved the video. One wrote: “The way she watched so intently and did so well, she has a bright future with the piano.”
After Lewis showed her the song’s keys, the youngster is subsequently seen practising it in the clip.
The West Lothian star gave her a high-five as spectators shouted and the touching video received over 1.8 million views and 235,000 likes.
Fans described the video as “sweet” and “wholesome” and thanked Lewis for sharing the video.
One commented: “She will never forget been taught piano by you! Thank you for being you and so selfless, Lewis.”
Another added: “The way she watched so intently and did so well, she has a bright future with the piano.”
The singer’s second album ‘Broken By Desire to be Heavenly Sent’ is set to be released on May 19, 2023, following a 31-date UK and European tour.
On January 23, he will perform at Aberdeen’s P&J Live, and the following night, in Glasgow, at the Hydro.