We will first describe the main results from the Tevatron concerning the
search for exclusive diffractive events, and the main physics motivation
to insstall forward detectors in the ATLAS experiment at the LHC, namely
QCD, diffractive Higgs production and the search for anomalous coupling
between photons and W/Z bosons. We will describe the detectors to be
installed in ATLAS (movable beam pipes, Si and timing detectors) and the
timescale of the project.