Japanese pop singer Seiko Matsuda will join Bruce Willis, Liv Tyler, Ben Affleck and Billy Bob Thornton in Touchstone Pictures’ disaster pic “Armageddon.”While not exactly a household name in the U.S., Matsuda has sold more than 30 million records in her native Japan, including 14 No. 1 albums and 26 consecutive No. 1 singles. Onscreen, Matsuda has starred in six major Japanese features and more than 100 television commercials. The Michael Bay-helmed “Armegeddon” will be Matsuda’s first English-language feature. She makes her American TV debut this fall in a two-episode guest-starring role on the USA Network series, “The Big Easy.” Matsuda’s deal was negotiated by Zoe Burns of Propaganda Management and her attorney John La Violette at Bloom, Hergott.