  We study the radiative corrections induced by the triple Higgs boson coupling
$hhh$ in the three body decay $h\to ZZ^*\to Zl\bar l$. We show that these
corrections are potentially sensitive to the specific value of this coupling in
the Standard Model and the Two Higgs Doublet Model (2HDM). These effects may
induce corrections to the integrated decay width of the three-body decay of
order few percent in the 2HDM and thus open a new window to test the Higgs
boson self interaction in physics beyond the standard model.
