Magnetism in materials has known two faces: ferromagnets (FM) and anti-ferromagnets (AFM). Recent theoretical proposals have brought into play a third flavour called altermagnetism. This version of magnetic order expresses characteristics of FM and AFM simultaneously by lifting spin degeneracies whilst exhibiting net zero magnetization. Yet, a clear-cut experimental fingerprint reflected in the excited state spectrum awaits detection. Here, we propose to use circular-dichroism resonant inelastic X-ray scattering (CD-RIXS) to probe the unique spectroscopic signatures of an altermagnetic candidate material. The interference of FM and AFM properties giving rise to this novel magnetic state should be well mirrored in the orbital and magnetic excitations. By momentum-mapping these excitations using CD-RIXS, we aim to provide unambiguous evidence for altermagnetism and pave the way to a systematic approach for the investigation of a wide range of candidate materials.