  The effect of initial state momentum-space anisotropy on invariant mass
dependence of HBT radii extracted from the leptonpair interferometry is
presented here. We have studied the Bose-Einstein Correlation Function (BECF)
for two identical virtual photons decaying to leptonpairs at most central
collision of LHC energy having fixed transverse momentum of one of the virtual
photons ($k_{1T}$= 2 GeV). The {\em free streaming interpolating} model with
fixed initial condition has been used for the evolution in anisotropic Quark
Gluon Plasma (aQGP) and the relativistic (1+2)d hydrodynamics model with
cylindrical symmetry and longitudinal boost invariance has been used for both
isotropic Quark Gluon Plasma (iQGP) and hadronic phases. We found a significant
change in the spatial and temporal dimension of the evolving system in presence
of initial state momentum-space anisotropy.
