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The fate of a massive star during the latest stages of its evolution ishighly dependent on its mass-loss history and geometry, with the yellowhypergiants being key objects to study those phases of evolution. We presentnear-IR interferometric observations of the famous yellow hypergiant IRC +10420and blue spectra taken between 1994-2019. Our 2.2 $\mu$m GRAVITY/VLTIobservations attain a spatial resolution of $\sim$5 stellar radii and probe thehot emission in the K-band tracing the gas via Na i double emission and theBr$\gamma$ emission. The observed configurations spatially resolve the 2.2$\mu$m continuum as well as the Br$\gamma$ and the Na i emission lines. Ourgeometric modelling demonstrates the presence of a compact neutral zone (Na i)which is slightly larger than the continuum but within an extended Br$\gamma$emitting region. Our geometric models of the Br$\gamma$ emission confirm anhour-glass geometry of the wind. To explain this peculiar geometry weinvestigate the presence of a companion at 7-800 au separations and find nosignature at the contrast limit of our observations (3.7 mag at 3$\sigma$). Wereport an evolution of the ejecta over a time span of 7 years, which allows usto constrain the opening angle of the hour-glass geometry at $<$10$^\circ$.Lastly, we present the first blue optical spectra of IRC +10420 since 1994. Themulti-epoch data indicate that the spectral type, and thus temperature, of theobject has essentially remained constant during the intervening years. Thisconfirms earlier conclusions that following an increase in temperature of 2000K in less than two decades prior to 1994, the temperature increase has halted.This suggests that this yellow hypergiant has "hit" the White Wall in theHR-diagram preventing it from evolving blue-wards, and will likely undergo amajor mass-loss event in the near future.

Tracing a decade of activity towards a yellow hypergiant. The spectral and spatial morphology of IRC+10420 at au scales