The actress has worn the 'Moonflower' dress, £57.99, on a number of occasions before - and it's clearly one of her favourites during warmer weather. It features two leg splits to the skirt, a pretty button-up silhouette and flattering cap sleeves.
Lily was spotted wearing the dress as early as 2015 during a stroll with her former boyfriend Matt Smith, so it's no longer available to buy.
Lily wore a floral dress from MinkPink
Downton Abbey star Lily recently returned to work to promote new film Rebecca via Zoom, appearing on a video call with co-star Armie Hammer, who shared a snapshot on his Instagram Story.
WATCH: Lily James and Armie Hammer star in new trailer for Rebecca
The 31-year-old has not yet publicly addressed the pictures of her and Dominic taken at the weekend during a short break in Rome.
Dominic, however, returned to his family home in Wiltshire on Tuesday morning and together with his wife Catherine Fitzgerald made a statement to the press, stating that they were "still together".
Dominic and his wife stepped out together on Tuesday morning
"I just want to say our marriage is strong and we are very much still together," he said.
The couple then handed out a piece of paper that bore the same words and contained both of their signatures.
The couple's written statement
Dominic married film producer Catherine in 2010 and the pair share four children. The couple dated at university but rekindled their romance after Dominic broke up with his girlfriend Polly Astor, with whom he shares a daughter. In June 2010, the actor married Catherine in her native Ireland.
Lily and Dominic pictured in 2011
The actor, whose on-screen credits include The Affair, Brassic and The Wire, is due to star in BBC drama The Pursuit of Love alongside Lily. Filming began in the Bristol and Bath area in July. Back in 2011, the pair also took to the stage together in Othello in Sheffield.