Liza and Conan met in 2000 when she appeared on his show in a skit about advertising. It was love at first sight for Conan and he "instantly" fell in love with Liza. Conan and Liza became engaged in July 2001.
 
Conan: "So you get engaged on the first Sunday of the break," O'Brien begins, using the second person to create a sense of emotional distance, "and then you have a whole week to call her friends, to call her friends' friends, and to call my friends. A week to get used to the idea. And to describe 60 times how I got the ring made and who made it." (For the society-page set: The fabled ring is a tasteful, custom-made, cushion-cut diamond set on a platinum band.)"

Liza and Conan were married on January 12, 2002 in Seattle, Washington in an afternoon ceremony at St. James Cathedral. The officiant was Conan's Harvard roommate and friend, Father Paul O'Brien. Their wedding reception was at Union Station in Seattle. 

Liza: “He was in the house all the time,” Powel recalls. “I said, ‘This can’t last – it’ll drive us crazy!’ Literally every 10 minutes, he’d poke his head in the room and say, ‘I don’t wanna bother you, but do you know where the Band-Aids are?’ ‘I don’t wanna bother you, but do you know how to use the phone?’ He was so sweet about it, and I felt like such a jerk. But seriously, I almost rented an office for him.”