  We present photometric and spectroscopic data sets for SN 2020pvb, a Type
IIn-P supernova (SN) similar to SNe 1994W, 2005cl, 2009kn and 2011ht, with a
precursor outburst detected (PS1 w-band ~ -13.8 mag) around four months before
the B-band maximum light. SN 2020pvb presents a relatively bright light curve
peaking at M_B = -17.95 +- 0.30 mag and a plateau lasting at least 40 days
before it went in solar conjunction. After this, the object is no longer
visible at phases > 150 days above -12.5 mag in the B-band, suggesting that the
SN 2020pvb ejecta interacts with a dense spatially confined circumstellar
envelope. SN 2020pvb shows in its spectra strong Balmer lines and a forest of
FeII lines with narrow P Cygni profiles. Using archival images from the Hubble
Space Telescope, we constrain the progenitor of SN 2020pvb to have a luminosity
of log(L/L_sun) <= 5.4, ruling out any single star progenitor over 50 M_sun.
All in all, SN 2020pvb is a Type IIn-P whose progenitor star had an outburst ~
0.5 yr before the final explosion, the material lost during this outburst is
probably playing a role in shaping the physical properties of the supernova.
