Many BSM scenarios predict the existance of new particles that couple to the third-generation fermions, and some can lead to final states with a Lorentz-boosted tau lepton pair- a region that experimentally has gone mostly unexplored. In this talk I will present the techniques and methods used to reconstruct and identify pairs of collimated tau leptons ("Boosted Di-Tau") produced at low (<~200 GeV) transverse momenta in ATLAS, and discuss the ongoing work on calibrating these objects and estimating their associated uncertainties.