Moon Ga-young & Koo Kyo-hwan Rekindle a 'What If' Romance in 'Once We Were Us,' Hitting Theaters December 31

By  Kim Ji-hye  | Nov 13, 2025

만약
If We
Koo Kyo-hwan and Moon Ga-young’s grounded romance "Once We Were Us" has locked a Dec. 31, 2025 theatrical release, and the first trailer just dropped.

"Once We Were Us" follows Eun-ho and Jung-won, former lovers who bump into each other a decade after a blazing romance, stirring up the traces of everything they once were―and everything they might still be.

The trailer, unveiled Nov. 13, opens with their chance encounter on a plane―their first meeting in 10 years―before rewinding to an awkward first hello, the slow drift into intimacy, and the years of laughter and tears that lead back to this charged reunion.
If We
Like any couple who once loved hard but couldn’t outrun real life, their story lingers. In the final beat, Eun-ho hesitates before saying, “There’s something I’ve always wanted to ask you. If…,” a line that hits anyone who’s ever carried a lingering what-if about a past love.

"Once We Were Us" marks the first big-screen romance for Koo and Moon, a pairing whose star power and finely tuned performances have generated buzz since production. Designed to resonate across ages and genders, the film taps into universal memories of love, breakups, and the fantasy of a chance reunion.

The film opens in theaters Dec. 31. 

(SBS Entertainment News | Kim Ji-hye)