  This article reports the first observation of the Moon and the Sun shadows in
the sky distribution of cosmic-ray induced muons measured by the KM3NeT/ORCA
detector. The analysed data-taking period spans from February 2020 to November
2021, when the detector had 6 Detection Units deployed at the bottom of the
Mediterranean Sea, each composed of 18 Digital Optical Modules. The shadows
induced by the Moon and the Sun were detected with a statistical significance
of 4.2{\sigma} and 6.2{\sigma}, respectively, at their nominal position. This
early result confirms the effectiveness of the detector calibration, in time,
position and orientation and the accuracy of the event direction
reconstruction. This also demonstrates the performance and the competitiveness
of the detector in terms of pointing accuracy and angular resolution.
