Premise: Gwen Stefani . , `` Rich Girl '' , and `` Hollaback Girl '' , the latter reached number one on the Billboard Hot 100 while also becoming the first US download to sell one million copies . `` Hollaback Girl '' is a song recorded by American singer Gwen Stefani for her debut solo studio album , Love .
Hypothesis: Gwen Stefani sings.
Label: ENTAILMENT