This study aims at establishing a new evidential category of interpersonal evidentiality (IE). IE grounds the illocutionary force of a statement in intersubjective knowledge shared by the speaker and other assumed members of society, regardless of whatever the source of information is. Drawing on Nuyts’s (1992, 2001a,b) work on the evidential application of the notion of intersubjectivity (Traugott and Dasher, 2002; Traugott, 1999, 2003, 2010; Verhagen, 2005) this paper argues that the perfect V-过 guo evolved in Modern Mandarin into a new IE construction. I provided a qualitative survey on 862 occurrences from the LCMC (Lancaster Corpus of Mandarin Chinese) proving the specific interpersonal dimension of V-过 guo as an evidential marker. I demonstrate in this work that IE can be seen as a proper typological category characterized by specifically grammaticalized items in many languages of the world. The theoretical implications of the establishment of IE as a typologically attested domain must lead us to redefine the primary semantics of evidentiality. The secondary claim of this work is thus to reconsider evidentiality as a non-modal domain primarily marking different types of ‘acquired knowledge’ rather than a ‘particular source of information’. Evidential constructions encoding specific sources of evidence must then be considered as a sub-class of the broader semantic scope of ‘acquired knowledge’ (AK). In essence, AK is here regarded as the primary pragmatic and semantic connotation of any type of evidential construction or strategy.