Dougie recently jetted to Australia with his bandmates as they are heading on tour with One Direction.
But not phased by hitting the road with his girlfriend's ex-boyfriend, Dougie told AAP Sydney: "We're all big enough and ugly enough to not really care."
He added: "We all have exes don't we... It's not a big deal, it's not like it was a marriage."
While Ellie has enjoyed a brief romance with Niall in the past, she is now currently loved-up with the former I'm A Celebrity star.
And the 'Burn' singer seems pretty smitten with her rocker beau!
The pair are often spotted looking blissfully in love - most recently in Paris - and Ellie has been known to publicly gush about her other half too.
Especially when talking about his vocal chords!
Admitting Dougie's voice makes her go weak at the knees, Ellie has previously said: "His voice literally makes me melt.
"He doesn't believe me! When he sings I just, like, collapse. I love his voice so much!"
The couple first began dating back in May last year.
Although keeping coy on their romance at first, Dougie then confirmed he and Ellie were an item, telling Fearne Cotton "all is good" between the pair.
Shortly after, Ellie too came clean about their relationship, telling Alan Carr: "[Dougie] is my man friend... boyfriend, traditionally."
She added: "He is a very lovely human being."
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