Significance: Singapore Court of Appeal clarifies that in determining whether a testator had testamentary capacity and/or knowledge of the contents of the will, the Court cannot regard all suspicious circumstances, whether or not they relate to the execution and preparation of the will, to be taken into account in determining if the usual presumption that a testator who has testamentary capacity knew and approved the contents of the will operates. Circumstances are relevant only if they attend or relate to the preparation and execution of the will. Otherwise, all kinds of non-related circumstances may be used to rebut the presumption. See [60]. Chee Mu Lin Muriel v Chee Ka Lin Caroline (Chee Ping Chian Alexander and another, interveners) [2010] 4 SLR 373 affirmed, clarified.