  Using the SDSS and Pan-STARRS1 survey data, we found a likely companion of
the recently discovered binary $\gamma$-ray radio-loud millisecond pulsar
J0621+2514. Its visual brightness is about 22 mag. The broad band magnitudes
and colours suggest that this is a white dwarf. Comparing the data with various
white dwarfs evolutionary tracks, we found that it likely belongs to a class of
He-core white dwarfs with a temperature of about 10 000 K and a mass of
$\lesssim 0.5$M$_\odot$. For a thin hydrogen envelope of the white dwarf its
cooling age is $\lesssim0.5$ Gyr which is smaller than the pulsar
characteristic age of 1.8 Gyr. This may indicate that the pulsar age is
overestimated. Otherwise, this may be explained by the presence of a thick
hydrogen envelope or a low metallicity of the white dwarf progenitor.
