The 'Dead in the Boot' singer struggles to recall all the words to the group's extensive back catalogue of tracks and has had to start using an autocue on stage which displays the lyrics.
Guy is finding it particularly tough to memorise the songs on the band's new album 'The Take Off and Landing of Everything'.
In an interview on the Geoff Lloyd Hometime Show on Absolute Radio, he said: ''There are still plenty of mistakes. I've still not learnt all my lyrics yet, I've got a teleprompt. It has become a little bit of a habit; I used to mock older front men for having them. But now if I haven't got the teleprompter, I start panicking and I forget my words. Two and a half thousand words the last album was.''
It seems Guy, 40, might have a bad memory in general as he has admitted he struggled to recognise Beyoncé and her husband Jay Z when he met her at the Glastonbury Festival in 2011 after her headline performance, despite her being one of the most famous women in the world.
The musician told ShortList magazine: ''There are gaping holes in my pop culture knowledge it's ridiculous. I was talking to Jay Z and Beyoncé for half an hour before I knew who they were. Everyone knows what Beyoncé looks like, but I thought [in real life] she'd be 7ft tall, statuesque like Tina Turner. Now I'm even doubting that Tina's 7ft tall. I just remember thinking, 'God, these two are good looking.' ''
The movie begins filming in the UK.
The 'Sherlock' and 'Doctor Strange' star joined Gilmour onstage at the Royal Albert Hall for a rendition of the Pink Floyd classic.