The 'Ooh La' hitmaker and the budding singer/songwriter reportedly got together after meeting through friends in the same circle and despite only being together for a short time, they already believed to be talking about moving in together.
The 33-year-old rocker - who has previously dated Georgia Jagger, the offspring of Sir Mick Jagger and his ex-supermodel wife Jerry Hall, and actress Mischa Barton in the past - has bonded with Ellie over music as Luke is said to be using his music industry experience to help get his girlfriend's career ''off the ground''.
A source told The Sun newspaper's Bizarre column: ''Luke is the happiest he's been in a long time since he got together with Ellie.
''They got introduced by mutual friends in the music world and haven't looked back since.
''Luke has been really keen to get Ellie's career off the ground and has been helping her work on her new single.
''She's also been a real support while he's been out at different gigs and they're now planning on getting a place together.''
The loved-up pair have made no secret of their romance on social media, with Ellie recently sharing photos of the couple on Instagram.
In one of the adorable pictures, she refers to the 'She Moves in her Own Way' hitmaker as the ''love of my life''.
The indie star revealed last month how the band's first album containing all original material in four years, 'Let's Go Sunshine', contains love letters to his new partner after suffering heartbreak in his previous relationship.
He said: ''I started off the record in quite a bad place.
''I'd had a pretty bad relationship that ended. My girlfriend at the time ran off with another singer.''
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