Complex sentence: Hagen is best remembered for her comic performance in "Singin' in the Rain" as the vain and talentless silent movie star Lina Lamont; she received an Academy Award nomination for Best Supporting Actress.
Split into simpler sentences: Hagen is best remembered for her comic performance in "Singin' in the Rain" as the vain and talentless silent movie star Lina Lamont. She received an Academy Award nomination for Best Supporting Actress.