As it turns out, Offerman actually fake proposed three times before he popped the question for real. He borrowed fake rings from the Will & Grace costume department, got down on one knee, and proceeded to lose said rings in over-the-top ways (think dropping it off the Eiffel Tower). So, when the real proposal came around, Mullally was taken by complete surprise.
The two were wandering the rose garden in London's Regent Park when they finally made it official. As Offerman put it, "We were heading down this path over a bridge by a Japanese garden, and all the ducks, insects, and frogs were furiously copulating around us. I feel like when our coupling is at hand, nature responds with a very positive reverberation. And I was right; she said yes." Well, color us smitten. (Huffington Post)