Transitions of two different stereoisomers of the He...ICl(X,v"=0) weakly bound complex, one with a T-shaped orientation and another that is most likely linear, have been observed in laser-induced fluorescence experiments performed in the ICl B-X region [Bradke and Loomis, J. Chem. Phys. 118, 7233 (2003)]. Here we present experimental and theoretical results aimed at confirming the previous assignments and at gaining additional insights into the He+ICl interactions. High resolution action spectra were recorded in the same region to identify those features that could be attributed to transitions of the He...(ICl)-Cl-35(X,v"=0) isomers and not to higher-order complexes, He-n...(ICl)-Cl-35, where ngreater than or equal to2, or (ICl)-Cl-37 containing species. Calculations of the rovibronic spectra of the He...(ICl)-Cl-35 complexes in the ICl B-X, 2-0 and 3-0 regions were performed using an ab initio potential energy surface for the He+ICl(X,v'=0) ground state [Prosmiti , J. Chem. Phys. 117, 7017 (2002)] and two different pairwise additive potentials for the He+ICl(B,v"=2,3) excited states [Waterland , J. Chem. Phys. 89, 7277 (1988); Gray and Wozny, J. Chem. Phys. 94, 2817 (1991)]. The rotation-vibration energies and wave functions for the He...(ICl)-Cl-35 complexes were obtained for all bound states with total angular momentum J<10 using both of these potentials. Electronic spectra were generated using these results, assuming that the transition moment lies along the ICl bond and is not perturbed by the presence of the helium atom. The calculations qualitatively reproduce the He...(ICl)-Cl-35 action spectrum and strongly support the previous assignments. The calculations also indicate that some of the spectral congestion observed near the linear band may be attributed to transitions of the linear isomer to multiple intermolecular levels in the excited state. Coriolis coupling strongly mixes He...ICl(B,v') states with rotational excitation, making simulations and assignments of the linear band observed in the experimental spectrum difficult. (C) 2004 American Institute of Physics.