It's A Sin wasn't the first time on TV for Callum Scott Howells.
The breakout star of Channel 4's new drama previously performed for Gary Barlow on his BBC One talent show Let It Shine.
He performed You'll Be Back from musical Hamilton for Gary and fellow judges Dannii Minogue, Martin Kemp and Amber Riley.
Callum's performance - which you can watch below - saw him make it into the Top 40 of the competition.
The then 17-year-old spoke about being head boy at is school, to the bemusement of American songstress Amber.
Following the show, Callum went on to star in She Loves Me in London's West End.
From multi-BAFTA Award-winning writer Russell T Davies (Queer As Folk, A Very English Scandal, Years and Years, Doctor Who), the five part mini series is set between 1981 and 1991, following the story of AIDS and charting the joy and heartbreak of a group of friends across a decade in which everything changed.
Callum is joined on the cast by Olly Alexander, from the band Years & Years, together with Omari Douglas, Lydia West and Nathaniel Curtis.
Other cast include David Carlyle, Keeley Hawes, Shaun Dooley, Tracy Ann Oberman, Neil Patrick Harris, Stephen Fry and Moya Brady.
Channel 4 recently revealed how the critically acclaimed show had broken online viewing records with over 6 million watching the series on All 4 so far.