  $\rho$ Pup is a $\delta$ Scuti F2 pulsator, known to host a main radial mode
as well as non-radial pulsations, with chemical peculiarities typical of
evolved Am stars. We present high-precision spectropolarimetric observations of
this star, obtained with ESPaDOnS at the Canada France Hawaii Telescope (CFHT)
in the frame of the BRITE spectropolarimetric survey. A magnetic field is
clearly detected in $\rho$ Pup, with a longitudinal field strength below 1 G.
This makes $\rho$ Pup the second known magnetic $\delta$ Scuti discovered,
after HD 188774, and a possible cool evolved counterpart of the recently
discovered ultra-weakly magnetic Am family.
