But his appearance in Beijing now rests on a ruling by a judge in London's High Court on Wednesday as Chambers bids to overturn a British Olympic Association byelaw, which bans athletes with a doping conviction from competing at the Games.
Millar served a two-year ban from 2004-2006 for a doping offense and under a then British Olympic Association bye-law was banned for life from Olympic competition.
In a statement, ParalympicsGB confirmed that it does not have a bye-law in relation to anti-doping that prevents athletes with a doping violation competing at future Paralympic Games.