“Late Night” comedy king Conan O’Brien tied the knot with willowy ad exec Liza Powel in a wacky laugh riot that had guests rolling in the church aisles!

Incredibly, even the priest who performed the January 12 wedding got into the act — doing a stand-up routine at the altar as the two said “I do” at St. James Cathedral in Liza’s hometown of Seattle, Wash.

“It was jokes galore!” a wedding guest told The ENQUIRER. “Father Paul O’Brien — he’s no relation but was Conan’s housemate at Harvard — had everybody rolling in the pews, literally.

“He joked about typical ‘Seattle’ priests, donning an umbrella, backpack and pointy wool cap over his vestments and walking around with a mug of Starbucks coffee.”

Then the padre asked guests to toss out adjectives that described Conan.

“When one guest blurted out ‘funny,’ the preacher quickly retorted, ‘I’m not so sure about that’ — which got a big laugh,” said the insider.

“As jokes turned to heartfelt praise for the bridal couple, there wasn’t a dry eye in the house.”

The bride — a former ad agency copywriter who met her knight in shining armor while doing a skit on his show — glowed in a pearl-encrusted lace and satin floor-length gown by Vera Wang.

After the ceremony, the 6-foot-4 groom joked, “Sorry about the rain!” as the newlyweds ducked out of the church and into a downpour.

Then the couple joined 450 guests for a reception at the refurbished Union Street Station. Celeb guests included Conan’s former sidekick Andy Richter, his “Late Night” band leader mighty Max Weinberg and “Friends” star Lisa Kudrow. An eight-piece band played swing music and big band tunes. The lavish event cost nearly $500,000, according to a source.

“No one seemed to have more fun than Conan and Liza,” said a guest. “They’re a perfectly matched pair in every respect.”