Updated project metadata. Cross-linking mass spectrometry (XL-MS) has progressed from studying purified protein assemblies in-vitro towards investigating the same assemblies in intact cells, tissues, and even whole organisms (so called “in situ XL-MS”). In situ XL-MS offers the great advantage of reporting on the architectures of protein complexes as they occur inside cells and tissues. Here we developed a complete workflow of in-situ XL-MS followed by purification, and employ it to investigate SARS-CoV2 protein inside the host cell. We focused on three Sars-Cov-2 proteins for which the structural information is either missing or incomplete: NSP1, NSP2, and the Nucleocapsid protein (N protein). Relatively little is known about the structures of these specific proteins, which was our motivation for choosing them. We were able to identify considerable cross-link sets, of in-situ origin. Integration of the cross-links with additional structural information allowed us to build almost complete models for NSP2 and the N protein.