LeoA is an isolated gas-rich dwarf irregular galaxy of low stellar mass and metallicity residing at the outskirts of the Local Group. Ages of the stellar populations in LeoA range from ~10Myr to ~10Gyr. A large stellar halo (up to the deprojected distance of ~1.7kpc was discovered based on Subaru wide-field photometry of red giant branch stars. We analysed HST WFC3 archive observation data in the field that is partly located beyond the previously known limits of the LeoA galaxy. We performed photometry of star-like objects in the F475W and F814W passbands and studied the spatial distribution of the Leo A stars below the horizontal branch. We report a discovery of stellar halo populations (subgiants and faint red giants) in the Leo A galaxy extending up to ~2.3kpc deprojected distance from the galaxy centre. Analysis of the colour-magnitude diagram suggests old (>5Gyr) stellar populations of very low metallicity (Z~0.0001).