The band will play a concert in Rio de Janeiro to celebrate their 30th anniversary.
A-ha stated in a press release the Norwegian trio will be reunited and they will be one of the headline acts at the Rock in Rio festival.
Both A-ha and Rock in Rio were founded in 1985. Both celebrate their 30th anniversaries in 2015.
A-ha performed in Brazil for the first time at the festival in 1991. They played to 198,000 fans at the Maracanã stadium, which at that time was a world record for the number of tickets sold for a music concert.
Vocalist Morten Harket said: “Earlier that week I sneaked in to the stadium to watch Guns N' Roses from the side of the stage while they played for 160,000 people. It was a fantastic concert and the first time I saw the size of the audience.”
Other big names during the nine days long festival in 1991 were INXS, Prince, George Michael and New Kids on the Block.
Keyboardist Magne Furuholmen confirmed: “The concert at the Maracanã stadium in 1991 was one of the greatest highlights in A-ha's career.”
He continued: “When the band got an offer to return in connection to the festival's 30th anniversary, it was impossible to turn it down.“
Guitarist Paul Waaktaar-Savoy said it took a long time before A-ha became used to playing their music live on stage.
He said: “I feel it was at Rock in Rio and the other concerts in South America, during that tour, that we finally achieved it.”