ABBA through the years 3rd April 1974: Swedish pop stars (clockwise, from bottom left), Benny Andersson, Anni-Frid Lyngstad, Agnetha Faltskog and Bjorn Ulvaeus of ABBA at Brighton. (Photo by Steve Wood/Express/Getty Images) (Steve Wood/Getty Images)
ABBA through the years 6th April 1974: Swedish pop stars (from left), Bjorn Ulvaeus, Anni-Frid Lyngstad and Agnetha Faltskog of ABBA playing live on stage. (Photo by Reg Burkett/Express/Getty Images) (Reg Burkett/Getty Images)
ABBA through the years Swedish pop group ABBA win the 1974 Eurovision Song Contest at the Dome in Brighton, with their song 'Waterloo', UK, 6th April 1974. From left to right, the band are Benny Andersson, Anni-Frid Lyngstad, Agnetha Fältskog and Björn Ulvaeus. (Photo by Evening Standard/Hulton Archive/Getty Images) (Evening Standard/Getty Images)
ABBA through the years circa 1974: Swedish pop group Abba arriving at London Airport. (Photo by Evening Standard/Getty Images) (Evening Standard/Getty Images)
ABBA through the years Swedish pop group Abba promote their single 'Waterloo' in Copenhagen, Denmark in 1974. (L-R) Björn Ulvaeus (Bjorn Ulvaeus), Agnetha Fältskog (Agnetha Faltskog), Anni-Frid Lyngstad, Benny Andersson. (Photo by Keystone/Hulton Archive/Getty Images) (Keystone/Getty Images)
ABBA through the years Swedish songwriter and musician Björn Ulvaeus and Norwegian-Swedish singer, songwriter, and environmentalist Anni-Frid Lyngstad of pop group ABBA performs on stage at the Royal Albert Hall, London, UK, 15th February 1977. (Photo by Frank Tewkesbury/Evening Standard/Hulton Archive/Getty Images) (Frank Tewkesbury/Getty Images)
ABBA through the years Singers Agnetha Fältskog (left) and Anni-Frid Lyngstad performing with Swedish pop group Abba on their third, and final, tour, 1979. (Photo by Keystone/Hulton Archive/Getty Images) (Matt Green/Getty Images)
ABBA through the years Singer Anni-Frid Lyngstad and pianist Benny Andersson performing with Swedish pop group Abba on their third, and final, tour, 1979. (Photo by Keystone/Hulton Archive/Getty Images) (Matt Green/Getty Images)
ABBA through the years Swedish singer Agnetha Fältskog in concert with the pop group ABBA, 1979. (Photo by Keystone/Hulton Archive/Getty Images) (Matt Green/Getty Images)
ABBA through the years LONDON - APRIL 6: Freda Lyngstad of ABBA arrives at the fifth anniversary performance of "Mamma Mia!," a musical based on ABBA's hits at the Prince of Wales Theatre on April 6, 2004 in London, England. (Photo by David Westing/Getty Images) (David Westing/Getty Images)
ABBA through the years LAS VEGAS - FEBRUARY 13: Former ABBA singer Anni-Frid Lyngstad attends the premiere of "Mama Mia!" February 13, 2003 at the Mandalay Bay Resort in Las Vegas, Nevada. (Photo by Scott Harrison/Getty Images) (Scott Harrison/Getty Images)
ABBA through the years NEW YORK - JULY 16: Executive Producer/ABBA founding member Bjorn Ulvaeus (R) and his wife Lena Kallersjo attends the American premiere of "Mamma Mia!" at the Ziegfeld Theatre on July 16, 2008 in New York City. (Photo by Stephen Lovekin/Getty Images) (Stephen Lovekin/Getty Images)
ABBA through the years LONDON - JANUARY 26: Anni-Frid Lyngstad and Bjorn Ulvaeus of Abba arrive at the ABBAWORLD Exhibition World Premiere at Earls Court on January 26, 2010 in London, England. (Photo by Samir Hussein/Getty Images) (Samir Hussein/Getty Images)
