It's not every day you witness a couple seducing each other in a Hilton hotel, but this is just one of the many voyeuristic treats afforded by this new show from Dante or Die.
On entry you're given a coloured rose buttonhole and asked to stand with those also bearing your particular shade of pastel (I was pink). Like any wedding, you make awkward introductions as you're ushered to the main event.
Taking place in six rooms of the Hilton Islington, the action is set ten minutes before the wedding of a particularly jittery bride and groom. The ten minutes are re-run six times, so each group can see what happens in every room.
It's a simple idea but the timing could easily go awry; fortunately writer Chloe Moss and devisers Daphna Attias and Terry O'Donovan (who also plays the best man) have choreographed the action with military precision. It all slots together like a neat theatrical jigsaw.
The random order that scenes are assigned means that every group gets a slightly different spin on events. So I laughed when I saw the grandmother wailing her lungs out in the mother-of-the-bride's bedroom; it was only a few rooms later that I realised she was screaming from the frustration of having to dress her disabled husband moments before.
A number of connections are cleverly established - phonecalls made in one room will ring in the next, raised voices you recognise from a previous scene permeate the walls of another.
The only character to enter every room, a hotel maid, rewinds down the corridor between each scene - a useful, if somewhat hackneyed narrative device.
As immersive experiences go, I Do strikes a happy medium between the voyeurism of Punchdrunk and the interactivity of You Me Bum Bum Train. You're free to wander around the hotel room as you wish, but beware if you happen to stand (or sit) on an actor's mark.
The action is extremely well executed by the ensemble, who must maintain energy as their scenes re-run like Groundhog Day. Credit especially to the young girl who must spend the majority of her scene patiently hiding - though I won't say where.
A final testament to the engrossing nature of the show is the fact that, when a man slammed his hotel door in frustration at the noise as we were leaving, I believed it to be part of the drama. "No, no," said our usher, "he's a genuine guest of the hotel."
Proof if it were needed that immersive theatre will never be to everyone's taste.
I Do is at the Hilton Islington until 3 August