  Recent surveys have demonstrated the widespread presence of UV emission in
early-type galaxies (ETGs), suggesting the existence of star formation in many
of these systems. However, potential UV contributions from old and young stars,
together with model uncertainties, makes it challenging to confirm the presence
of young stars using integrated photometry alone. This is particularly true in
ETGs that are fainter in the UV and have red UV-optical colours. An unambiguous
way of disentangling the source of the UV is to look for structure in UV
images. Optical images of ETGs, which are dominated by old stars, are smooth
and devoid of structure. If the UV is also produced by these old stars, then
the UV images will share this smoothness, while, if driven by young stars, they
will exhibit significant structure. We compare the UV and optical morphologies
of 32 ETGs (93 per cent of which are at $z<0.03$) using quantitative parameters
(concentration, asymmetry, clumpiness and the S\'ersic index), calculated via
deep UV and optical images with similar resolution. Regardless of stellar mass,
UV-optical colour or the presence of interactions, the asymmetry and clumpiness
of ETGs is significantly larger (often by several orders of magnitudes) in the
UV than in the optical, while the UV S\'ersic indices are typically lower than
their optical counterparts. The ubiquitous presence of structure demonstrates
that the UV flux across our entire ETG sample is dominated by young stars and
indicates that star formation exists in all ETGs in the nearby Universe.
