Two piece garment introduced. The most dramatic recent change was the two-piece garment in 1979. In a letter to Church leaders dated December 15, 1979, the First Presidency announced the introduction in February 1979 of two-piece temple garments. The new style garments were offered in addition to, and priced about the same as, the regular one-piece variety. No explanation for or description of the new garments was given.
[The Temple Timeline (Masons, Ancient Temples, Garments and a Lot More), http://www.exploringmormonism.com/the-temple-timeline-masons-ancient-temples-garments-and-a-lot-more/]