Globular cluster progenitors may have been detected by textit{HST}, and are predicted to be observable with textit{JWST} and ground-based extremely-large telescopes with adaptive optics. This has the potential to elucidate the issue of globular cluster formation and the origins of significantly helium-enriched subpopulations, a problem in Galactic astronomy with no satisfactory theoretical solution. Given this context, we use model stellar tracks and isochrones to investigate the predicted observational properties of helium-enriched stellar populations in globular cluster progenitors. We find that, relative to helium-normal populations, helium-enriched (${Delta}Y=+0.12$) stellar populations similar to those inferred in the most massive globular clusters, are expected, modulo some rapid fluctuations in the first $sim$30 Myr, to be brighter and redder in the rest frame. At fixed age, stellar mass, and metallicity, a helium-enriched population is predicted to converge to being $sim$0.40 mag brighter at $lambda approx 2.0, {mu}m$, and to be 0.30 mag redder in the textit{JWST}-NIRCam colour $(F070W-F200W)$, and to actually be fainter for $lambda lesssim 0.50 , {mu}m$. Separately, we find that the time-integrated shift in ionizing radiation is a negligible $sim 5%$, though we show that the Lyman-$alpha$ escape fraction could end up higher for helium-enriched stars.
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