  Jupiter's atmosphere is enriched with heavy elements by a factor of about 3
compared to proto-solar. The origin of this enrichment and whether it represent
the bulk composition of the planetary envelope remain unknown. Internal
structure models of Jupiter suggest that its envelope is separated from the
deep interior and that the planet is not fully mixed. This implies that
Jupiter's atmosphere was enriched with heavy elements just before the end of
its formation. Such enrichment can be a result of late planetesimal accretion.
However, in-situ Jupiter formation models suggest the decreasing accretion rate
with increasing planetary mass, which cannot explain Jupiter's atmospheric
enrichment. In this study, we model Jupiter's formation and show that an
migration of proto-Jupiter from $\sim$ 20 AU to its current location can lead
to a late planetesimal accretion and atmospheric enrichment. Late planetesimal
accretion does not occur if proto-Jupiter migrates only a few AU. We suggest
that if Jupiter's outermost layer is fully-mixed and is relatively thin (up to
$\sim$ 20\% of its mass), such late accretion can explain its measured
atmospheric composition. It is therefore possible that Jupiter underwent
significant orbital migration followed by late planetesimal accretion.
