She grinned: "I was attracted because of the writing.... and the chance to work with Kevin.
"He was brilliant. There's a moment when he walks into the hospital and says, 'I want to see my wife' and the all the females on set were like, 'Ahhhh!' "
Michelle plays Kevin's sick wife Penny in the surreal drama, which is based on Homer's Oddysey.
His character Peter embarks on a bizarre journey through a hospital to see his missus, including being robbed by a dodgy cab driver and seduced by a horny nurse.
Kevin - who also plays Dr Owen Hunt in US hospital drama Grey's Anatomy - revealed: "Luckily, knock on wood, I have NEVER spent a night in a hospital. The longest time I've been in one was on this shoot and of course on Grey's Anatomy, although that's just a set.
LA-based Kevin, 36, admits he's missing Scotland and enjoyed coming back to film the show, which also features fellow Trainspotting star Ewen Bremner and telly veteran David Hayman.
He said: "It was a relief to be among my own again. I shot my first film in Glasgow so it felt like coming home for me, even though I'm from Elgin.
"I was worried the sentiment on set would be, 'Here he comes, the bloke who went off to Hollywood,' but that didn't happen. It was brilliant seeing folk I hadn't seen in ages."
One Night In Emergency is on BBC1 at 9pm on January