The U.S. producers says they're writing for Rihanna, Usher and a slew of Korean acts

After producing a major hit for Girls' Generation with "Mr.Mr." — the year's most-watched K-pop video to date and a No. 3-peaking hit on the K-Pop Hot 100 — U.S. production team the Underdogs are helping out boy band EXO for their new single "Overdose."

The 12-member act will promote the track in both Korean and Chinese, splitting into two sub-unit groups: EXO-K for Korea and EXO-M for China; the 'M' standing for singing in Mandarin Chinese. Though it's one of the most anticipated comebacks in K-pop, the release has been delayed indefinitely in South Korea with the entertainment industry on a complete hold out of respect to the Sewol ferry disaster. While EXO-M has been promoting live (see below), the Underdogs' Harvey Mason and Damon Thomas tell Billboard they have high hopes come official release time.

"The track is exciting, it's got a lot of energy," says Mason. "It's got some R&B elements, but it's still got a great melody and a big pop hook. It has elements of contemporary radio and it's kinda similar to what's going on over here. For us, it's a perfect combination of a lot of different styles of music. It gives them an opportunity to do what they do — which is create videos, choreography, sing and there's a little bit of rap."

After their January 2012 debut, EXO rocked the K-pop scene last year with breakout hit "Growl": The southern hip-hop track hit No. 3 on the K-Pop Hot 100 and made waves stateside as one of America's most-watched videos and best-selling singles for 2013 K-pop. Mason and Thomas are confident fans will take to "Overdose" similarly.

"I think it's comparable," Mason says of the singles. "There's definitely differences in the way we make our records and our vocal arrangements, which I think will be good for them to show off their vocal ability...We think it's a great record and we feel really great about it coming out as a single."

WATCH: EXO Talks 'Growl' & Global Success in Video Interview

While the duo have made a name for themselves crafting hits for solo stars like Justin Timberlake, Beyonce and Chris Brown, they add that they aren't intimidated by keeping the 12 different EXO voices or Girls' Generation's nine singers in consideration. "That's not a normal thing, to write a song for 12 people," Thomas explains. "You just jump in there and make the best of it like we did. You can't base it off of a number of people."

Mason adds, "We always try to keep in mind who we're making the record for. You realize that it's going to be multiple people singing, but you can't really change the way you write. You just have to try and write a really great song and then figure out how you implement all the different voices after that."

For the Underdogs, "Overdose" is another creation of the hitmakers' long-term relationship with Korean record label SM Entertainment— home to EXO, Girls' Generation, TVXQ!, f(x), SHINee and more. And the duo couldn't be happier sending their beats halfway around the world.

"SM is not thinking about any in-the-box record, they're trying to do things that are different," says Mason. "They're trying to do music that is unique to their artists, they're not afraid to talk about certain concepts or take risks musically. We enjoy making those kind of records. We can be daredevils and SM generally is like, 'That's really cool. Let's go for it.' So we love that.

"They obviously came back for more records and more singles, following 'Mr.Mr.' with 'Overdose.' They've been very supportive and hopefully it's working well for them. We really like working with them."

While remaining tight-lipped about details, the guys also tease new songs they recorded during a recent recording trip to Seoul. The duo promise "five or six records that we did that will be amazing, game changers" with SM's established acts and still-to-debut groups.

Meanwhile, the Underdogs add that they've been writing for Rihanna and Usher's new albums, as well for U.S. boy band Suite 44, who they say is being overseen by Epic Records CEO Antonio "L.A." Reid. Look out for the Underdogs' music on the silver screen too with upcoming works on the "Pitch Perfect 2" soundtrack and in the Mick Jagger-produced James Brown biopic, "Get on Up."