An original experimental approach is presented to test under compression ultra-thin films on compliant substrates. The sputtering chamber was modified to permit deposition of the film on an untreated polyimide substrate tensily stressed by a Deben™ device. Exploration of the compression response was made possible with the film being loaded, when unloading the polyimide dogbone substrates. The compression response of an ultra-thin film of gold (18.5nm) deposited onto the elastically loaded substrate was investigated using synchrotron X-ray diffraction. In contrast to tensile loading reported in the literature, the elastic compression could be explored up to −0.5% (−440MPa as compared to 290MPa).