Lacey, 25, starred as 18-year-old Molly Dawes in the BBC drama in March 2013 and is returning to reprise the role for a new five-part series.
The show followed Molly as she turned her back on her troubled life in east London and signed up to the British Army, eventually serving as a trained solider in Afghanistan.
Last night, the BBC shared a sneak peek picture of Lacey - who plays Stacey Branning in EastEnders - on the set of Our Girl.
The star is wearing full army camouflage gear and is smiling while holding a clapperboard.
Alongside the photo, the caption read: "Filming is underway on a five part series of #OurGirl, starring @LaceyTurner."
The BBC haven't yet announced when Our Girl will air, but it will be this year. Exciting!
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