Kevin McHale admits working on 'Glee' is like "organised chaos".

The actor - who plays wheelchair-bound singer Artie Abrams in the musical drama series - has revealed the 12-18 hour-long-days on set leave them exhausted, as they have to learn songs, practise dance routines and memorise the scripts for several episodes at once.

He explained: "Thank God we know nothing else. We have eight days to make an episode, but while we're doing Episode Two we're rehearsing for Episode Three and getting the songs we are going to be doing in Episode Four. It's organised chaos. Fridays are the longest - we call them Fraturdays because they always run into Saturday."

As well as having a hectic working week, the group of TV stars - also including Cory Monteith, Lea Michelle, Dianna Agron, Chris Colfer, Matthew Morrison, Jane Lynch and Amber Riley - are also in demand on their weekends, something which can cause tension amongst them.

Kevin explained to the Daily Mail newspaper: "And then at weekends we do press and photoshoots. When we get tired, we snap. But we're like brothers and sisters, we know when to stay away from each other."

However, the stars are adamant their hectic lifestyles have more pros than cons.

Amber added: "It's hard work, but it sure beats staying at home doing nothing but dreaming."