Monsieur Mellow – Roll River, Roll (feat. Jackson James Smith) out now

by the partae April 1, 2026

written by the partae April 1, 2026

Australian songwriter/producer Callum MacDonald (best known as a core member of Brisbane R&B/soul outfit daste.), continues to carve out a new lane with his solo project, Monsieur Mellow. This week, he shares his latest single, “Roll River, Roll”, the next taste of his forthcoming debut solo EP.

Launching the project in January with the smooth, groove-led ‘Paris Strut’, and quickly following it up with ‘Slow Down’ featuring Sydney artist Taj Ralph, Monsieur Mellow has been steadily building a world that leans into warmth, nostalgia and late-night sway. Now, “Roll River, Roll” sees him teaming up with Brisbane singer/songwriter Jackson James Smith for a collaboration that feels both effortless and overdue.

Built around soulful vocal samples and glowing brass lines, the track locks into a slow-burn rhythm that feels timeless. Lush trumpets set the tone early, while the groove carries that signature Monsieur Mellow balance — music that feels lived-in yet immediate, equally suited to solitary reflection or a dancefloor moment shared with someone close.

Speaking on the track, Callum shares; “I’ve always been drawn to soulful vocal samples, so in August last year I remember spending a few days digging through acapellas that really spoke to me. A handful from the London collective Soothsayers immediately clicked as they carried the warmth I’d been hearing in my head for this project. From the start, I knew where I wanted the sound to lean.

With Monsieur Mellow, I’m always chasing that sweet spot between groove and nostalgia. I want the music to feel lived-in, like something that moves you in the moment but also feels like it drifted in from another decade. There’s a certain sway I’m after, that slow-burn rhythm you could dance to with someone you love as the night rolls on.

The foundation of “Roll River, Roll” came together quickly once the brass lines and chorus vocal sample locked in. The trumpets really set the tone, and everything else flowed from there. I’d been hoping to work with Jackson for a long time, but I’m a big believer in waiting for the right song. I feel lucky he connected with it. His vocal ended up being the final touch on a track I already loved, and it lifted the whole thing exactly where it needed to go.”

With each release, Monsieur Mellow further defines his solo identity — one rooted in groove-heavy production, soulful textures and a deep reverence for classic songwriting. “Roll River, Roll” continues that evolution, setting the tone for what’s to come from his debut EP later this year.