In the process of searching the Hubble Space Telescope archive, we have serendipitously discovered three populous Large Magellanic Cloud (LMC) clusters with ages that place them in the LMC ``age gap.'' These clusters-NGC 2155, SL 663, and NGC 2121-turn out to have [Fe/H] ~ -1.0 and ages of ~4 Gyr. This puts them in the ``age gap'' between the intermediate-age LMC clusters, the oldest of which are ~2.5 Gyr old, and ESO 121-SC03, which has an age of ~9 Gyr. The addition of these three clusters to the LMC age-metallicity relation has reduced the discrepancy between the age distribution of the LMC clusters and the field stars. Furthermore, it indicates that searches to find more clusters older than ~2.5 Gyr in the LMC are crucial to a better understanding of its global star formation history. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.