Who would guess that a comic famous for his profanity-strewn act was a trained opera singer? Who would know another comedian famed for his mock reporting on the “The Daily Show With Jon Stewart” was a decorated lieutenant colonel in the Marine Corps Reserve?

Unlike many comedians who have been reduced to easy-to-swallow bits ready for public consumption, Jim Jefferies and Rob Riggle, who perform this weekend at John Ascuaga’s Nugget, have more to offer than the usual Hollywood shallowness.

“I tell stories, you know,” Jefferies said. “I’m a bit of a bullshitter and all storytellers have been bullshitters throughout time. I think I’m kind of like a grandfather telling stories and jokes, they’ve been doing it forever.”

The Australian native spares few taboos in his comedy, from race to disabilities, from religion and sex; he happily tackles what other comics avoid. Call him raunchy or coarse, but the one label he will embrace is brutally honest.

“I find it a privilege that I can talk about God,” Jefferies said of his jokes about religion. “I ponder about his nonexistence every week when I sit down to write. In fact, I probably think about it more than many believers.

“In the UK, people are primarily atheists, so there it’s no big deal,” Jefferies continued. “The audience gets more excited about it here (in America), I guess it limits my career here. You can’t reject 85 percent of your audience and not expect consequences. … But if you’re a Christian and you have such a strong faith then you should be able to take it. I don’t get offended when I see a priest on a plane. That’s the beauty of an opinion, everyone has one and it can’t hurt you unless you let it.”

In 2000, Jefferies made the leap to the United Kingdom from his native Australia to hone his comedy after doing a year of stand-up, according to The Herald newspaper in Scotland. Jefferies attracted attention when he was attacked by an audience member at the Manchester Comedy Store in England in 2007. The video of the attack became his most-watched video on YouTube, according to The Herald.

Rolling with the punches on and off the stage, Jefferies soon incorporated the video into his act.

He appeared at several comedy festivals, including the Edinburgh Fringe, and was soon on BBC comedy shows such as ”Never Mind The Buzzcocks,” “Have I’ve Got News For You,” and a regular spot on BBC Radio’s “Fighting Talk.”

Bigger stages soon beckoned after the overseas release of his “Contraband” video. He then scored a 2009 HBO special, “I Swear to God,” and moved to Los Angeles, according to The Herald.

Since his HBO success, the 34-year-old has been touring with his “Alcoholocaust” tour for the last year.

Refusing to tone down his act for Hollywood marketability, he dealt with criticism from the Jewish community for the title of his latest act, he said.

“Well, I think you’ve got to watch something to be offended by it, but they hadn’t done that,” Jefferies said.  “But they’ve retracted some of what they said. I think they thought it was going to be a very different act from what is actually was. But it was over the word Holocaust, but I don’t think they own that word. There have been other holocausts.”

Rob Riggle is another comedian with unlikely roots. The 41-year-old former “Saturday Night Live” and “The Daily Show With Jon Stewart” cast member grew up in Overland Park, Kan. He was in Marine flight school when he decided to follow his dream of being a comic, he told Marines Magazine in 2009.

Riggle then transferred to a public affairs job with the Marines in New York City, where he moonlighted as an improv comic, the comedian’s website said.

“Ten years later, almost to the day, in September 2004, (SNL producer) Lorne Michaels called me and asked me to join the cast,” Riggle told the Kansas-based news website Lawrence.com in 2007. “It took a long time, but I kept my eye on the ball, so to speak, and I kept working and working and working and eventually it panned out.”

Riggle was on “Saturday Night Live” for a year and landed a job on the “The Daily Show” until 2008 when he left to co-star on CBS’s “Gary Unmarried.“

The comedian also has appeared in several films between deployments in Kosovo, Liberia and Afghanistan, including “Talladega Nights: The Ballad of Ricky Bobby,” “Unaccompanied Minors,” and “The Hangover.”  

As part of the April Fools’ Comedy Weekend, Jefferies and Riggle will be appearing at 9 p.m. on Friday and Saturday respectively in the Celebrity Showroom at John Ascuaga’s Nugget. Tickets are $20 for one performance and $35 for both. Tickets are available by calling 800-648-1177 or 356-3300 or by visiting www.jannugget.com.