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We report the detection of X-ray emission from the hyperluminous infrared galaxy IRAS at and its properties obtained from XMM–Newton observations. Although the X-ray emission is very faint and the data are noisy, a prominent line-like feature in the observed 3–4 keV range is inferred from both photometric and spectroscopic techniques. It indicates an X-ray spectrum dominated by 6.4-keV Fe Kα emission and the presence of a Compton-thick active galactic nucleus. Our estimate of the luminosity of the illuminating source , required to produce the observed Fe Kα emission in reflection from cold matter, means that the hidden quasar nucleus accounts for a significant fraction of the large bolometric luminosity. The soft X-ray emission below 2 keV is found to be spatially extended and probably of a separate origin. The temperature and bolometric luminosity ( and ) obtained from a thermal spectrum place this X-ray source on the relation of galaxy clusters. The possible association with a galaxy cluster can be added to the list of remarkable similarities between IRAS and another hyperluminous infrared galaxy IRAS , both of which have bolometric luminosities dominated by hidden quasar nuclei. Our result on IRAS illustrates how difficult it is to detect Compton-thick Type II quasars at , particularly if their bolometric outputs do not rival the hyperluminous population. [ABSTRACT FROM AUTHOR]