Five years after they started, and at least two years after they might reasonably have been consigned to the Right Said Fred novelty band scrap heap, party-rocking uncle-nephew duo LMFAO continue their strangely inexorable march to the top of the charts.

Members Redfoo, 36 (born Stefan Gordy), and SkyBlu, 25 (born Skyler Gordy), are the son and grandson of record industry heavyweight Berry Gordy. They have two full-length albums, including their latest, “Sorry For Party Rocking”; numerous hit singles; and one dance step, the shuffle, which they popularized but did not invent, to their credit. Their biggest hit, “Party Rock Anthem,” recently spent six weeks at No. 1, has sold more than 3 million digital copies and racked up more than 273 million (yes, million) hits on YouTube.

According to Redfoo, LMFAO, who appear at the Fillmore Silver Spring on Thursday, make “calculated party rock using the house and electro dance scene, with songs.” Basically, they’re weed-and-women-loving faux doofuses with one eye on marketing opportunities (so far there’s a clothing line and a new DJ app) and another on the dance floor.

Phoning in from Dublin the night after LMFAO appeared at MTV’s EMA awards, RedFoo discussed partying with Justin Bieber (“went out and celebrated at the @LMFAO after party and did a little shufflin with the fellas. #goodtimes,” Bieber tweeted ), and the fallout from last year’s infamous Mitt Romney Incident, in which SkyBlu and the GOP hopeful tussled onboard a 2010 Air Canada flight after SkyBlu reclined his seat into Romney’s lap. Each side claimed the other had become violent. No charges were filed.

Reading Justin Bieber’s tweets about your after-party, he sounded like he had a wild time. What did you do to that boy?

We met backstage and he’s a cool dude. We did the after-party and he just showed up. He’s a true party rocker in that when he shows up, he comes out and puts his hands up, and the crowd’s like [makes screaming noises]. That’s the essence of LMFAO and party rock. Embrace the moment and entertain the people. He came up next to us when I was DJing and he was all putting his hands up. He’s amazing.

Are you amazed at how far you’ve taken this whole thing?

Yeah. I could say I’m amazed. A lot of the stuff was like a dream. A very specific dream. We wanted to be the biggest in the world. We saw Michael Jackson and we said, we want to experience what it is to be Michael Jackson-esque. Just entertaining the people and making the world feel happy and dance. And so we focused on that.

Do you think the recession helped you, that people are looking for escape music?

If we had done it 10 years ago, when Yahoo was $200 a share or when the Internet boom was happening and the economy was booming, I think it would have been more successful, because those people would have had more reason to party. It would have been more champagne showers. We would have been invited to bigger parties, on yachts.

You were a day trader not too long ago, which must have been a more stressful job than this.

It’s stressful if it’s your way of living and paying your rent. But for me it’s a hobby. I had extra money, and I was having fun learning and experimenting. Of course I want to win so I want big gains, but it was really just learning about trends. You can make money on the way up and you can make money on the way down.

Are you tempted to dip back into it now that you have money?

No. No, no, no. I’ll go to Vegas and I’ll play some roulette, some blackjack, but I feel like I’ve grown out of get-rich-quick [stuff]. It’s not really interesting to me to make money that way anymore. I feel like investing in really solid stuff that I can control. I felt when I was gambling that the house always wins, and it was always like, how can I become the house? But when you’re a band, you are the house because you can write the songs, you can wear your own clothes, you can pick where your show is. I can choose my own cards, basically. Gambling is a risk, but it pays off. We’re the number one video on YouTube, you know?

Do you think about mixing some more serious stuff in with the party stuff, or would that be too much of a risk?

Well, if you listen to some of our songs, they are kind of serious. Like [“Sorry” track] “Best Night,” a lot of people think that would be the greatest wedding song ever. And that would be okay with us, because a wedding is a party . . . And then we have “We Came Here to Party,” based on the Mitt Romney Incident.

It is?

Yeah, we’re talking about politicians . . . [After the incident] both parties were fighting. Mitt Romney’s fans were attacking the LMFAO fans and the LMFAO fans were going back and forth. We’re basically saying, everyone’s a human and we all can get along, and how you do that is at the party, you know?