  We consider the effect of a partial transpose on the limit $*$-distribution
of a Haar distributed random unitary matrix. If we fix, $b$, the number of
blocks, we show that the partial transpose can be decomposed into a sum of $b$
matrices which are asymptotically free and identically distributed. We then
consider the joint effect of different block decompositions and show that under
some mild assumptions we also get asymptotic freeness.
