The One Direction star is said to have recorded the ballad without band mates Liam Payne, Louis Tomlinson, Zayn Malik and Niall Horan after writing his own music.
A video entitled 'Don't Let Me Go (feat Harry styles) was uploaded to YouTube yesterday (13 June), although there has been no official confirmation that it is actually him singing.
The voice in the video belts out: "Don't let me, don't let me go, cos I'm tired of feeling alone."
We're not sure whether it actually is Harry or not, and we're convinced we can hear Liam, although the other voice is said to be his friend Sam McCarthy.
Whether Harry has recorded a solo song, there has been a mixed reaction from One Direction fans.
One said: "I'm crying, I can't stop listening to this music, it's amazing."
However another warned: "Nick Jonas started doing a solo song for 'fun'. You know what happend to the Jonas Brothers, so I'm scared for One Direction..."
Have a listen and tell us what you think below, is it Harry? The best comment from across the website each week wins £50.