The singer has been dating the American Idol winner since early last year (12), and they were recently rumoured to be engaged after Derulo pretended to propose to Sparks in his Marry Me video.
He has now revealed they have made their love permanent with matching tattoo tributes.
Derulo tells British newspaper the Daily Star,"On my right elbow there's a 'more than' sign and 'yesterday' which is a matching tattoo which Jordin and I both got. It means 'I'll love you more than yesterday' and we always strive to be more than yesterday."
The importance of the inkings is echoed in the title of his latest album, Tattoo, with Derulo saying, "It is called Tattoo because... body art... stays with us for the rest of our lives. Our life experiences help create how beautiful a person is - the same as body art. My parents aren't so keen though - my dad tells me off even more than my mum does."