The squad prepared for tonight's clash with Benfica by taking part in a training session at the historic Estadio Nacional in Lisbon on Tuesday morning.
The old stadium, which holds nearly 40,000, is still used to stage the national Cup Final every year and was the scene of Celtic's famous European Cup triumph over Inter Milan in 1967, after which they were dubbed the Lisbon Lions.
The lads warmed up by splitting into two teams within which they had to run half the length of the pitch keeping the ball up among themselves. Ten press-ups was the punishment for the losing team.
They then moved onto possession drills before finishing up with a crossing and shooting drill before returning to the team hotel for downtime ahead of the game, kick off 7.45pm.
Scroll through the images above to view the session.