  The present experimental study illustrates how large deformations attained by
nuclei due to cluster formation are perceived through the giant dipole
resonance (GDR) strength function. The high energy GDR $\gamma$-rays have been
measured from $^{32}$S at different angular momenta ($J$) but similar
temperatures in the reactions $^{4}$He(E$_{lab}$=45MeV) + $^{28}$Si and
$^{20}$Ne(E$_{lab}$=145MeV) + $^{12}$C. The experimental data at lower J
($\sim$ 10$\hbar$) suggests a normal deformation, similar to the ground state
value, showing no potential signature of clustering. However, it is found that
the GDR lineshape is fragmented into two prominent peaks at high J ($\sim$
20$\hbar$) providing a direct measurement of the large deformation developed in
the nucleus. The observed lineshape is also completely different from the ones
seen for Jacobi shape transition at high $J$ pointing towards the formation of
cluster structure in super-deformed states of $^{32}$S at such high spin. Thus,
the GDR can be regarded as a unique tool to study cluster formation at high
excitation energies and angular momenta.
