According to TV Line, Dean Cain and Helen Slater have joined the cast of CBS' upcoming series ‘Supergirl’ in mystery roles. Both actors are no strangers to the DC world. Cain is best known for playing Clark Kent/Superman on the 1990s series "Lois & Clark: The New Adventures Of Superman" and later appeared on the CW's … Continue reading Dean Cain and Helen Slater Join ‘Supergirl’ Cast In Mystery Roles