Solar prominences are clouds of cold and dense chromospheric plasma suspended in the very tenuous ambient corona. They are called prominences when they are seen at the limb and scatter light from the underlying atmosphere, and filaments when they are observed as absorption features above the solar disk. They are supported against gravity and isolated from the hot environment by the magnetic field. Though maintaining such structures and governing their evolution, little is known about the actual magnetic field topology (and strength) of solar prominences. One of the reasons is that measuring full spectropolarimetry of such tenuous structures is extremely challenging and very few data sets are available. Also, the subsequent interpretation of the polarimetric signatures (in the Hanle-Zeeman regime) is not straightforward. In this talk I will review the present state of knowledge on solar prominence magnetic fields. Since the late 80s, it is well known that the corona of rapidly rotating stars also hold clouds of dense material, probing that the corona of late-type stars is a complex medium with non-homogeneous density and temperature distributions. These clouds were first reported by Collier Cameron & Robinson in 1995 and they are commonly called ``stellar prominences'', since their physical properties present some similarities with solar prominences. Though much more observationally challenging, stellar prominences have been detected and characterised on several fast rotators. In this talk, I will briefly review this research field and show very preliminar analysis of the prominences on a dwarf M star (HK Aqr). I will show that large amplitude oscillations similar to those reported in the Sun are also present in the prominences of HK Aqr.