Deformations of (maximal) supergravity induced by gauging non-abelian subgroups of the duality group, follow an intruiging group-theoretical pattern in which generically all p-form gauge fields seem to play a role. The representations of the $p$-forms are precisely in agreement with M-theory considerations. As it turns out the situation can be captured in terms of the very-extended Kac-Moody algebra $E_{11}$.