As one of the world’s greatest bands, Radiohead don’t do things by half. Their current world tour has seen them sell out gigs at some of the biggest arenas on the planet. Tonight and tomorrow that includes the Palais Omnisports de Paris-Bercy – a 17,000-seat show for which every last ticket has been snapped up.

They continue on Sunday at Amsterdam’s cavernous Ziggo Dome, to the same capacity crowd. But eagle-eyed fans will notice this Saturday they have a night off. Or at least some of them; their drummer Philip Selway will be hard at work preparing for one of the toughest gigs of his career... in a small theatre in East Oxford.

“I’m taking part in a marathon play reading called a Playathon,” he says.

“The whole thing takes place at the Pegasus and people will be able to come along and read from a play or piece of prose. For me it’s very much a case of getting up and giving it a go.

“It’s on a night off for me. I’ll be in Paris the night before and Amsterdam the night after. Fortunately these European dates are easy to get back from, otherwise I wouldn’t be able to take part in anything like this.”

The Pegasus Playathon, which starts tomorrow and runs until Sunday, is being held to celebrate the 139-seat youth theatre’s 50th anniversary. Volunteers will take it in turns to read from a play, poem, musical or operetta in return for donations to funds.

The drummer, who as part of Radiohead has shifted more than 30 million albums, will take to the stage with EastEnders director Steve Finn. The pair will perform a reworked version of Noël Coward’s Private Lives, with Philip taking on a very different persona from the understated and softly spoken star Radiohead fans know.

“Steve will guide me through the different passages, which will be great,” he says. “I did a drama degree in Liverpool but I haven’t done anything like this since.”

It all seems like a change for a man better known for wielding the sticks behind Thom Yorke and co. “Absolutely,” he says. “On stage you are very much yourself – but that is usually me with a grimacing face as I am concentrating so much. I am looking forward to this, and being guided by one of the best in the business.”

It may not measure up in size to London’s O2 arena, where he played two sold-out shows earlier this week, but for Philip, who lives with his wife Cait and children Leo, Jamie and Patrick in West Oxfordshire, the performance is no less important. Indeed, it is probably more significant; Philip is a patron of the Magdalen Road theatre and takes a huge personal interest in its work.

His link to the venue came through his work with The Samaritans, where he supported a collaboration between the two organisations called The Listeners. Since then he has helped raise the profile of music at the theatre, establishing music technology programmes for young people.

Last year he helped commemorate its half-century by performing a series of solo shows featuring songs from his album Familial.

“This ties in with the 50th anniversary of Pegasus which kicked off last year with that run of three shows,” he says.

“It also highlights the strategy of Pegasus, which is such an inclusive theatre. Anybody can come in and take part in events and know there’s a fantastic safety net. It can be a big deal putting yourself on the line but there is a professional set-up. It’s a wonderful theatre to perform in. I like Pegasus’ emphasis on personal development which is the right angle. It nourishes, stretches and is educational. And it’s open to all – whether they have a nascent interest or are fully fledged. And not just performance, but writing and music technology. Everything is done to a high standard.”

He goes on: “This is an important event and it will be good to be part of that. And, selfishly speaking, I’m looking forward to getting up and working with Steve. It’s out of my normal experience. After all, when else would I be able to come along and have a go at something like this?”

So, with Philip working with the director of ’Enders, is he, I wonder, a fan of the soap?

“I have been,” he says. “But I have completely lost touch with it now. I haven’t got the time.”

It has, he admits, been a long year and one leaving little time for anything outside the band. “This year has always been about Radiohead,” he says. “I am in that headspace now and we all feel anything we do outside the band leads back into it.

“We are in a good position; we’ve got a good back catalogue, so songs come along which we haven’t played for a while and we can dust down. We get a lot out of playing them.”

Is there a current favourite? “I like a song called Planet Telex from The Bends,” he says. “We’ve just resurrected it. And because we now have two drummers — myself and Clive Deamer from Portishead — it has given it a whole new life.”

“It’s good to be back out and doing the shows,” he goes on. “The best connection with our music comes from seeing us live.”

But with Oxford missing out on a tour date, might there, I ask, be a repeat of one of the band’s greatest ever shows — their 2001 show in the city’s South Park? “Wouldn’t that be nice!” he laughs. “Who knows?”

While a repeat of that historic gig remains unlikely, however, the former Abingdon schoolboy is fiercely proud of his local links. “This is where I grew up, where my family grew up,” he says. “My life is deeply rooted here. The band also grew up around here and it is central to the way we work. We’ve all got families so know the importance of spending time here — especially when we’ve been away a lot during the year.”

And finally... when can we expect to hear the next Radiohead album? Philip laughs, pauses thoughtfully and replies: “Your guess is as good as mine!”

The Pegasus Playathon

  • Pegasus
  • Tomorrow (Friday), 5pm to Sunday 7pm
  • Also featuring The IT Crowd’s Rachel Bavidge and Oxford poet Craig Raine
  • Tickets £12 – 01865 812150 pegasustheatre.org.uk
  • To donate, visit justgiving. com/pegasusplayathon or text 70070, type in PEGS 50 and the amount in £ donated.