PASADENA

In an A-list pairing you don't often find on television, Matthew McConaughey and Woody Harrelson team up in the mesmerizing eight-part crime thriller, "True Detective" (9 p.m. Sunday, HBO).

The two men, who appeared for a panel session here at the TV critics press tour, play mismatched detectives searching for a bizarre serial killer in the backwoods of Louisiana. The story, written by novelist Nic Pizzolatto, takes place over 17 years, toggling between past and present.

McConaughey and Harrelson, both Texas natives, are longtime pals who previously starred together in the big-screen comedies "EDtv" (1999) and "Surfer Dude" (2008). But for "True Detective," they had to suppress the laughter and put aside their friendship -- at least while they were on camera.

Michelle Monaghan, left, and Woody Harrelson on stage during the True Detective panel discussion at the HBO portion of the 2014 Winter Television Critics
Michelle Monaghan, left, and Woody Harrelson on stage during the True Detective panel discussion at the HBO portion of the 2014 Winter Television Critics Association tour at the Langham Hotel on Thursday, Jan. 9, 2014 in Pasadena, Calif. (Photo by Richard Shotwell Invision/AP)

"With this project we didn't use a lot of our normal kind of shorthand, the way we kind of finish each other's sentences and (stuff)," Harrelson said, referring to the dynamic created by the icy relationship between the two cops. "He was fully in character and very much an island. It was very different."

Added McConaughey, "This is the first time we worked together where there's real opposition. ... This was not about us coming together. We were not playing catch back and forth."

Just the opposite, in fact. McConaughey's character, Rust Cohle, is a loner with a bleak world view that eats away at Harrelson's Martin Hart. The two men butt heads and grow apart as the macabre murder impacts them in profound and disturbing ways. Along the way, the hypnotic saga becomes more about the characters than the actual case.

McConaughey and Harrelson, both busy film stars these days, say they had no hesitation to commit to a TV show.

"All I knew is I read the first two episodes, and I was in," McConaughey said. " ... Some of the best drama going on has been on television, in comparison to some films. So it was a 450 page film, is what it was."

Both men shine in their roles, but McConaughey is forced to slip into what he calls a "deep, dark dude, a man with his own demons," and to make a major physical transformation over the 17-year period.

Actor Matthew McConaughey speaks onstage during the ’True Detective’ panel discussion at the HBO portion of the 2014  Winter Television Critics
Actor Matthew McConaughey speaks onstage during the 'True Detective' panel discussion at the HBO portion of the 2014 Winter Television Critics Association tour at the Langham Hotel on January 9, 2014 in Pasadena, California. (Photo by Frederick M. Brown/Getty Images)

"I can't imagine anyone playing that part better. He was phenomenal," said Harrelson of his partner. "It was different than any other part I've seen him play before, and he knocked it out of the park."

For McConaughey, it's another major highlight in what has been an remarkable career hot streak, which has included highly praised roles in three films last year: "Mud," "Dallas Buyers' Club" and "The Wolf of Wall Street." He was asked to reflect on his success, but declined.

"I haven't really been looking in the rearview mirror for a while, and I hope I don't," he said. "This is nice to talk about but in no way am I in a retrospective mode."

Viewers should enjoy the work while they can. "True Detective" is intended to be an anthology series, meaning that a second season, if there is one, will feature a new story, characters and locations.

Contact Chuck Barney at Facebook.com/BayAreaNewsGroup.ChuckBarney, or Twitter.com/chuckbarney