Marilyn McCoo (born September 30, 1943) is an American singer, actress, and television presenter, who is best known for being the lead female vocalist in the group The 5th Dimension, as well as hosting the 1980s music countdown series Solid Gold. Since 1969 she has been married to singer Billy Davis, Jr., the founder and co-member of the 5th Dimension. She also has a four-octave vocal range.