This article aims to assess of the Velocity Distribution Function (VDF) in the plume of two Hall thrusters firing in cluster configuration. A cluster offers various advantages compared to a large single thruster unit: a broad operating envelope as thrusters can be fired individually or together, cost reduction as many thrusters are built, redundancy when one thruster fails, and thrust vectoring capabilities depending on the thruster arrangement. In this case, the specific impulse remains unchanged but the thrust level is the sum of the thrust of each thruster [1, 2]. A relevant point for operation is the physical interaction between the ion beam produced by each thruster. This interaction, which still is poorly grasped, certainly has an impact on the thruster performances and on the spacecraft environment. In this contribution, we experimentally examine the interaction between the plasma plumes in a cluster of two lower-power xenon fueled Hall thrusters by means of Laser-Induced Fluorescence spectroscopy on singly-charged metastable Xe + ions. Those preliminary experiments clearly evidence plume overlap and ion penetration and invasion.