We construct a CFT with \mathfrak{sl}(2,\mathbb{R})_k symmetry at the `tensionless' point k=3, which is distinct from the usual \mathrm{SL}(2,\mathbb{R})_{k=3} WZW model. This new CFT is much simpler than the generic WZW model: in particular its three-point functions feature momentum-conserving delta functions, and its higher-point functions localise to covering map configurations in moduli space. We establish the consistency of the theory by explicitly deriving the four-point function from the three-point data via a sum over conformal blocks. The main motivation for our construction comes from holography, and we show that various simple supersymmetric holographic dualities for k_{\rm s}=1 (k=3) can be constructed by replacing the \mathrm{AdS}_3 factor on the worldsheet with this alternative theory. This includes in particular the prototypical case of \mathrm{AdS}_3 \times \mathrm{S}^3 \times \mathbb{T}^4, as well as the recently discussed example of \mathrm{AdS}_3 \times \mathrm{S}^3 \times \mathrm{S}^3 \times \mathrm{S}^1. However, our analysis does not require supersymmetry and also applies to bosonic {\rm AdS}_3 backgrounds (at k=3).
