A heterobimetallic complex with the first unsupported bond between an actinide and a group 13 element, (CpSiMe3)3U-AlCp* (Cp* = C5Me5) (1), was synthesized by reaction of (CpSiMe3)3U and 1/4(Cp*Al)4 in toluene. Density functional theory calculations indicate that the U-Al bond exhibits some covalent character resulting from a Cp*Al-->U charge-transfer.