The Scottish singer gave the track to the 'Came Here For Love' hitmaker after it didn't make the cut for his record-breaking debut album, and next week fans will get to hear the song - which the DJ has transformed into a dance track and features the vocals of the 'Say You Won't Let Go' singer.
An insider told The Sun newspaper's Bizarre column: ''Lewis is obviously known for his ballads but wrote this song ages ago and knew it wasn't quite right for him so he wanted someone else to pump some life into it.
''He sent the demo to Sigala after hearing the DJ's remix of his track 'Someone You Loved'.
''He's completely reinvented 'Lasting Lover' as a dance track.
''Lewis is not singing on it, as he is working on his second album at the moment, but he gave his blessing for James to sing it.''
The 'Before You Go' singer's demo getting the Sigala treatment comes after Lewis quipped that he's not releasing any new music in 2020 because everyone has ''suffered enough''.
The BRIT Award-winning star may have been busy penning new material during lockdown, but he doesn't plan on sharing any of it with his fans until 2021, as he joked they've been through enough sadness amid the coronavirus pandemic.
The 'Grace' said: ''Hopefully I will release a new song and a new album next year.
''I won't release another album this year or anything.
''I think people have suffered enough in 2020 they don't need another song from me.''
He continued: ''So far we've written like 50 songs for it and like three or four of them are good, which is a good ratio I think.
''I am surprised at how productive I have been during lockdown as I thought I'd just sit in my pants all day and that would be it.''
And those expecting a collaboration from Lewis will be disappointed, as he admitted he's not willing to ''split the cash'' with a duet partner.
He said: ''I think for my second album I want to keep it just me, as the problem is if you do a collaboration with someone you need to split the money.
''And I am a selfish man and I do not want to split the cash with anyone!''
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