The Brady Bunch (1969)

S3E22 My Fair Opponent

As a prank, Molly Webber, a girl next door, is chosen as the hostess for Banquet Night. This leads Marcia to embark on a mission to give Molly a stunning makeover. While Marcia achieves amazing results, she soon realizes that her efforts may have backfired, as she now finds herself competing against the new and captivating version of Molly.