Arguably the greatest team on the planet come to Scotland tonight in what is the standout home fixture in a glamourous group of death for Celtic.
While the visit of Barca would have most teams hoping for something short of total embarrassment, the Hoops can afford to be a little more optimistic. The sides met at this stage of the competition last season and Celtic won 2-1. Goals from Victor Wanyama and teenager Tony Watt saw Rod Stewart have the night of his life (which is saying something).
The goalscorer for Barcelona on that incredible night was Lionel Messi, and if Celtic were already optimistic they could upset the odds again, the fact the world's greatest player is missing through injury will buoy the Buoys.
Somewhat unlucky to lose their opening game away at AC Milan, Neil Lennon will know that in a group that also includes Ajax, points at home are essential. They don't come tougher than this though.
KICK-OFF: Tuesday, 7.45pm
Celtic 2 (Wanyama, Watt) Barcelona 1 (Messi), Champions League, group stage, November 2012
Barcelona 2 (Iniesta, Alba) Celtic 1 (Samaras), Champions League, group stage, October 2012
Barcelona 1 Celtic 0, Champions League, knock-out phase, March 2008
Celtic 2 (Hesselink, Robson) Barcelona 3 (Messi 2, Henry), knock-out phase, February 2008
Barcelona recorded their seventh league win in as many games at the weekend - making it their best ever league start.
Barcelona have not won an away game in the Champions League in three attempts.
Lionel Messi scored a hat-trick against Ajax in Barcelona's most recent Champions League game - it was his fourth in Europe's top competition.
Celtic are unbeaten in the league this season, but their two full cup games this season have ended in defeat, including against Scottish Championship side Morton.
Celtic win: 9.4
Barcelona win: 1.41
TV: Live on ITV at 7.45pm, highlights on ITV at 10.35pm.