NEW YORK – Winding down for the night, Gary Jules turned on “American Idol” — his guilty pleasure — and left the room to watch surfing videos on his computer. Then he heard some eerily familiar notes.

It was Adam Lambert — one the top finalists on the most popular TV show in the country — performing Jules’ arrangement of the Tears for Fears song “Mad World.”

“I ran out and I was like, `I knew he was gonna do it! I knew it!’” he recalls. “I’ve been waiting for years for somebody to do it. I thought David Cook was gonna do it last year for sure. … As soon as I saw that guy Adam on `American Idol,’ I was like, ‘Oooh, this could be it.’”

The singer-songwriter deserves at least some of the credit for Lambert’s haunting performance that earned a rare standing ovation from “American Idol” judge Simon Cowell.

Jules covered the ’80s song on his 2001 album, “Trading Snakeoil for Wolftickets.” His stripped-down, slowed-down version, recorded with producer Michael Andrews, was featured in the cult movie “Donnie Darko” the same year.

The song topped the charts in Britain in 2003 but is little known to U.S. listeners.

Lambert, a 27-year-old actor known for his daring performances and vocal range, had the coveted final spot that often goes to the front-runner on the Fox network competition. But on Tuesday, it wasn’t entirely an advantage.

Because the show ran eight minutes over schedule, Lambert’s performance was cut off for many DVR users, causing mass outrage in spite of the fact that the missing footage is widely available on the Internet.

Jules, 40, thinks Lambert put a signature spin on his cover-of-a-cover.

“It was fantastic,” he says. “He has a beautiful voice. … I heard his Michael Jackson cover and I heard some of his other stuff, and I think that he’s probably one of the most — if not the most — interesting performer I’ve ever seen on `American Idol.’”

He’s especially excited about the possibility of Lambert or someone else giving him credit for the arrangement on Wednesday night’s results show. Especially after the standing-O from Cowell, who called Jules the day after his version of “Mad World” hit No. 1 overseas.

“Simon said that he loved it,” he remembers. “That he thought it was a beautiful performance. That he thought it was better than the first one, better than the original and that it was very very heartfelt and blah blah blah — and I was, like, really grateful except I had no idea who he was.”

The song was a collaboration between Jules and Andrews, his best friend; they recorded it in 15 minutes, Jules says, while Andrews was writing the score for “Donnie Darko” and helping Jules make his acclaimed “Snakeoil” disc on a budget of less than $100.

After that, “Mad World” took on a life of its own. Tears for Fears singer Roland Orzabal called Jules and praised the arrangement as “better than the original,” he says. Jules heard that Radiohead singer Thom Yorke played it on the radio in England during a guest VJ spot.

“The song is phenomenal. … I got really super-personal, heartfelt sometimes really creepy, odd emails from people. I’ve had like bizarre suicidal pen pals and stuff like that,” says Jules, whose musical influences include Michael Stipe, Paul Simon and Neil Young.

It’s an important week for Jules: He has two songs on TV. The single “Beautiful” from his latest album, “Bird,” will be heard during the season-finale of the NBC football-and-family drama “Friday Night Lights.” In 2007, his song “Falling Awake” charted on Billboard after being featured during an emotional segment on ABC’s “Grey’s Anatomy.”

Jules — who jokingly calls his music “wuss rock” and counts fellow singer-songwriters Jason Mraz and Jack Johnson as friends — thinks the exposure could translate to album sales.

“I need to kind of get people to know my name as well as they know some of my songs. … Obviously, the story is `Forget the publicists, just get yourself on `American Idol‘ every once in a while,’” he says.