Ladysmith Black Mambazo has covered a broad range of music during its 40-plus years together, from indigenous South African styles to the children's music of last year's Grammy Award-nominated "Songs From a Zulu Farm." Now the vocal group has some a bit more spiritual in its sights.

"We've been experimenting with gospel music -- American gospel music in the old style and South African music in the old style," the group's Albert Mazibuko tells Billboard.com. "We've been testing the waters just to sing it to ourselves and see if it sounds good. We feel that it's time for us to relax and do whatever pleases us, unlike before, where we were singing about struggle and making people strong, and we felt that mission. Now we feel we can celebrate with our music."

While there are no firm plans to record or release a gospel album, Mazibuko says he'd also like to see the Ladysmith "collaborate more with young artists," but the troupe's latest release, the two-disc "Ladysmith Black Mambazo and Friends" celebrates its work with previous work with others, including its Grammy Award-winning "Graceland" pairings with Paul Simon to songs it recorded with Dolly Parton, Sarah McLachlan, Melissa Etheridge, Taj Mahal, Josh Groban, Emmylou Harris and others.

Paul Simon Talks 'So Beautiful' Album, 'Graceland' Reunion Tour

"This is a dream come true for us," Mazibuko explains. "From the beginning we wanted to unite people with our music. So if somebody comes and says, 'Let's do something together,' that is what we wanted to do. We wanted the world to come together in peace and connect and then share ideas and make people happy and sing." And while "Graceland" certainly vaulted Ladysmith to worldwide acclaim, working with Parton was one of the group's happiest moments, according to Mazibuko.

"She is very famous to our wives," he explains with a laugh. "Even before we joined Paul Simon they were playing her music, so we were very excited to meet this lady... I remember when we met her we were in New York and we recorded the song called 'A Peace Train.' We were talking with her for maybe 20 minutes or so, then she disappeared and came back with different attire from head to toe. We said, 'Whoa, we are at a fashion show in the studio here!' That was the most enjoyable recording that we had, and a great experience."

Mazibuko says he hasn't heard anything yet about a possible "Graceland" tour to celebrate the 25th anniversary of the first tour to support the album, but Ladysmith and Hugh Masakela did reunite with Simon last July in South Africa for a performance that Joe Berlinger filmed for his new documentary, "Paul Simon: Under African Skies," which premiered at this year's Sundance Film Festival and will be part of a "Graceland" box set due out in May.

"It was wonderful," Mazibuko says of the recent session. "First of all we looked at each other and everyone said, 'Wow, you've grown old!' so we were laughing about that. But it was wonderful. It brought back all those memories and it was a great, wonderful thing. We wanted to keep the music as pure as it is...because it was such a wonderful thing that happened for all of us."