The front room of the Kelly Writers House is set up like a nightclub — candles on little tables, dimly lit.

A disembodied voice announces, “The man, the mystery, Jonathan London is here for you.”

That’s not all that’s here for you. London (C’01) bounds up to the front. “For those of you who didn’t have a nice Valentine’s Day, this show is for you.” Turns out at the end, it’s also for his girlfriend. But more about that later.

About 40 people stay for an hour-and-a-half comic monologue about Jonathan London’s love life. They laugh. They cry.

“I expected there to be five people and I expected them to be silent through the entire thing,” London said a couple of days later. “I looked up and I saw all these people and I thought, I don’t want to tell them this much about me.”

He told about embarrassing sex; he imitated his loving but nosy Mexican mother, who has an uncanny sense of timing her phone calls.

So why did he tell all, after all? “To build confidence,” said London, formerly a “bookish kid” until tragedy transformed him.

He became an extrovert three-and-a-half years ago, after his older brother Daniel was killed by a drunk driver.

“My younger brother [Paul] was captain of the j.v. basketball team. He was loud, all this stuff. ... We kind of switched roles.”

London started speaking for Mothers Against Drunk Drivers. He began hitting the open-mike nights at comedy clubs in his home town of Austin, Texas — “Berkeley in the desert,” he said during his routine. He came to Penn and sought out the campus radio stations. And this year he screwed up his courage to deliver his Valentine’s Day comedy routine.

He said he reminded himself of the terrible night his brother was killed and told himself, “If you can’t stand up before a group of people and tell them about girlfriend woes ...”

London is a familiar voice for those who listen to late-night programming on Penn’s two radio stations. He’s the host of “xxHungoverxx,” with his friend Kevin McCaffrey, from 10 p.m. to midnight Wednesdays on student-run WQHS, and they do the same show on WXPN (see “Radio”) under another name, “Radio Revolution,” the first Sunday of each month from 12:30 a.m. to 2 a.m. The show mixes punk, rock ’n’ roll and alternative music.

It also includes radio dramas. “It’s a comic book on the air, the radio equivalent of ‘South Park,’” he said. The two hosts do all the voices, improvising as they follow a preordained story line. “We have characters, sound effects. It’s not unlike the old radio dramas.”

All that experience lay behind his monologue, which included dialogues — his role was live — with his “mother” and others recorded on CD along with sound effects and “cheesy love songs ... like Elton John and Air Supply and the Carpenters.”

He’d been thinking about the monologue since September, but once he got the music idea, he needed only one day in December to write the comic tale of his transformation from dating dork to a man ready for love.

The monolgoue was a valentine to his girlfriend, Kirstin, who was sitting up front. Then he gave her yet another token of his love — two hamsters to replace her runaway pet. But hamster number one had turned up shortly after he made the purchase. Now Kirstin owns three hamsters — and a sweet and funny public valentine.