Acetylates 5-aminomethyl-2'-deoxyuridine (5-NmdU) to produce 5-acetylaminomethyl-2'-deoxyuridine (5-AcNmdU) on DNA as a step in the pathway leading to thymidine hypermodifications in the viral genome (PubMed:34522950). As a final result of the pathway of hypermodification, 5-acetylaminomethyl-2'-deoxyuridine (5-AcNmdU) substitutes for a subset of thymidines in the viral DNA (PubMed:34522950). These modifications probably prevent degradation of viral genome by the host restriction-modification antiviral defense system (PubMed:34522950). 5-aminomethyl-dUMP in DNA + acetyl-CoA = 5-acetylaminomethyl-dUMP in DNA + CoA + H(+) Belongs to the acetyltransferase family.