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Recent advances in high-cadence surveys have revealed a new class of luminous and rapidly-evolving transients comma which are not intrinsically rare but pose significant challenges to conventional supernova models. In 2018 comma an extreme member of this class comma AT2018cow comma was identified. AT2018cow was the first rapidly-evolving transient discovered promptly at a small distance comma facilitating intensive multiwavelength follow-up. However comma despite being the most extensively studied transient of its class comma its true nature is still debated comma with possibilities ranging from tidal disruption events to the failed explosion of a massive star. Late-time observations of rapidly-evolving transients offer a means to break this degeneracy comma and HST images taken during 2020 (more than 700 days post-explosion) reveal a UV-bright point source at the precise position of AT 2018cow. However comma the nature of this underlying source is ambiguous as it can be interpreted as either the emission from the transient or an underlying stellar population--both of which would place significant constraints on the origin of AT2018cow. Recently comma a shallow HST SNAP observation in 2021 showed tentative (2-sigma) evidence for fading in the optical (where the source is faint). Here we request a single epoch of HST-UVIS imaging to confirm the transient nature of the source and measure its rate-of-decline comma necessary to constrain the power source. Extrapolations based on physically and observationally motivated models show that the source may be detected during this Mid-Cycle at 25.5-26.0 mag (AB). We emphasize that HST is the only current instrument with the resolution and depth capable of probing this source.