Robert John "Mutt" Lange (born 11 November 1948) is a South African record producer and songwriter. He is known for his work in the studio, producing many of rock's most famous albums. He has produced albums for, or otherwise worked with, artists such as AC/DC, Def Leppard, The Boomtown Rats, Foreigner, Michael Bolton, The Cars, Bryan Adams, Huey Lewis and the News, Billy Ocean, Celine Dion, Britney Spears, The Corrs, Maroon 5, Lady Gaga, Now United, Nickelback, and Muse. He also wrote and produced songs with his then-wife, Canadian singer Shania Twain. Her 1997 album Come On Over, which he produced, is the best-selling country music album, the best-selling studio album by a female act, the best-selling album of the 1990s, and the 9th best-selling album in the United States.