A cappella group Home Free are a new name in country music, but they've been around since long before their first-place finish in Season 4 of The Sing-Off in 2013. In fact, they've got years of history behind them -- and a die-hard fan base that any artist would kill for.

Brothers Adam and Chris Rupp, then teenagers in Mankato, Minn., founded Home Free in 2000. The quintet's other three members have changed over time, but the current lineup -- the Rupps, plus Austin Brown, Rob Lundquist and Tim Foust -- has been together in its entirety since early 2013.

"It was a hobby. They didn't start it to succeed; they didn't start it thinking it would be anything other than something they got to do for fun for a while," Brown tells The Boot of the Rupp brothers. "But they kept going, and I think that's really all that matters."

It was on The Sing-Off that Home Free really found their identity, Brown explains. Before their time on the competition TV show, the group performed "a mix of all sorts of stuff;" it was the show's executives that advised them to focus on their country repertoire, and it proved to be fortuitous advice, as covers of everyone from Johnny Cash to Florida Georgia Line helped them emerge victorious.

"It was the one thing we needed," Brown says simply.

Since their win, Home Free have released three major-label albums: Crazy Life and a Christmas album, Full of Cheer, both of which came out in 2014 -- and both of which landed in the Top 20 on the Billboard Top Country Albums chart (No. 8 and No 12, respectively) -- and their brand-new record, Country Evolution.

The new disc features five original compositions, nine covers ... and two appearances by country icons. The Oak Ridge Boys collaborate with Home Free on their classic "Elvira," while Charlie Daniels is featured on Home Free's version of "The Devil Went Down to Georgia."

"Working with some of those big names has really validated us," Brown explains. "... There hasn't been anything like what we do for a long time -- really, since the Oak Ridge Boys."

Validated Home Free within the country music industry, that is. Even before those star-studded collaborations, if the a cappella group was looking for validation, they needed to look no further than their passionate fans. Brown says they're not "groupies," as some have suggested, but more like "group families" -- moms and daughters who "treat us like we're their sons or nephews or something."

"It's a blessing and a humbling experience to realize how much these people have come to care about us," Brown reflects. "... We have a very minor celebrity, but a very dedicated fan base, [and] in a time when most celebrity is very transient and short term, we have a fan base that we know is going to be there as long as we're here, and it's a very comfortable thing to think about spring-boarding off of.

"We don't feel like we have to rush. We can take our time to get this right, as long as we keep moving forward, because they love us so much," he continues, "and hopefully, we can help that grow to a larger fan base that loves us just as much as our current fan base."

An engaging live show is another one of the keys to Home Free's success -- and one of the ways they'll likely continue to grow their fan base.

"Most of [our fans] have seen us in a live show ... They get to see us as genuine people," Brown explains. "... Everything will change with you see us live. That's where we really show you who we are and what we're capable of."

In addition to the musical aspects of their performances, at each concert, Home Free "almost immediately break down the fourth wall" for their audience.

"We like to make you feel like you're there with us in a conversational setting," Brown says. "... We cut up a lot ... Every night is a little different ... and everyone seems to like it, and, more importantly, we like it."

Home Free have found a way to harness that feel offstage, too: Fans continue to eat up their creative music videos, as well as behind-the-scenes footage and other exclusive content that they create and distribute via Patreon, a platform that allows fans to pay for access to such content. All of the money the group makes through the site goes back into creating more videos.

"It's actually blown our minds out successful we are on there," Brown says. "It's, hands down, the most important part of our presence online right now."

If it sounds like the Home Free guys are a busy bunch, that's because they are.

"We don't have much time off, ever," Brown says, "... but it seems worth it so far."

The group currently has tour dates scheduled until just before Christmas, and Brown says that there are more coming, as well as more new music.

"There have been a lot of people coming to us and really taking an interest in what we're doing -- a lot of people in the industry," Brown explains, so the quintet is hoping to work with a big-name producer for their next album, and maybe even get a song on the radio.

"As as long as we feel like our peak is yet to be found, as long as we still feel like we're rising, we're all in it together," he says. "We just want to make this as successful as we can ... and we want to see how far we can go."

Country Evolution is available for download on iTunes.