Using the stellar radius determined using the Hipparcos parallax (blue solid lines) and the stellar density measured via the Spitzer light curve (solid green lines), we measure the mass and radius of KELT-11 to about 10% (red point with large errors). The Torres et al. (2010) relations impose a mass constraint based upon the spectroscopic temperature and ﹩\mathrm{log}g﹩ (dash-dotted brown lines), and imposing these relations upon the fit gives a resulting lower mass and radius for KELT-11 given the measured density (leftmost red point). If we were to hypothetically model what will be possible with the final Gaia data release by using the Hipparcos parallax with the Gaia parallax uncertainty, we would measure a mass and radius for KELT-11 that is significantly different from model expectations (central red point). A hypothetical stellar density measured via TESS would make the difference even more acute. This illustrates the power of precise transit photometry and precise parallaxes to give essentially empirical stellar mass and radius measurements, with uncertainties small enough to meaningfully test stellar models. We consider the most likely stellar parameters to be the leftmost model-influenced point, under the assumptions that the Torres et al. (2010) relations are correct and that the Hipparcos parallax is 1σ low. A precise measurement of the KELT-11 parallax via Gaia will test these assumptions.