If you happened to catch this PSA on television in Britain this month, you might be left wondering if it is—could it somehow possibly be?—real footage. And that's the point. The spot, from Grey London, shows an unborn baby drifting around inside the womb in what is surely the most real-seeming in-utero footage ever. It is, however, all CGI. "The craft and technique that Digital Domain and [Radical Media director] Chris Milk put into making the ad was amazing, and the end result looks so brilliantly life-like that we hope people will walk away from it questioning whether it's real or not," says Grey deputy executive creative director Vicki Maguire. The ad, for the British Heart Foundation, even has the baby do the voiceover (in a child's voice). She talks about how she might inherit a heart condition from her parents. "I wanted to create a sincere and simple piece of film, forging a deeply emotional connection with girl who needs saving even before she is born," says Milk, who also made Arcade Fire's stunning interactive experience The Wilderness Downtown. "The story is told in a world that is familiar but still a mystery. She's invited us in because she has something to say. Something vital." Credits below. CREDITS Client: British Heart Foundation Agency: Grey London Creative Director: Vicki Maguire Copywriter: Clemmie Telford Art director: Lex Down Managing Partner: Sarah Jenkins Business Director: Eve Bulley Account Manager: Grant Paterson Account Executive: Isaac Hickinbottom Agency producer: Vanessa Butcher Creative producer: Gemma Hose Planner: Ruth Chadwick Media agency: PHD London Media planner: Monica Majumdar Production company: @radical Media Director: Chris Milk VFX: Digital Domain Editor: Brian Miller Producer: Ben Schneider/Sam Storr Post-production: Digital Domain Soundtrack composer: Vampire Weekend Audio post-production: Grand Central