Keanu Reeves stepped out in London on Monday for the premiere of John Wick: Chapter 4 (Picture: Dave J Hogan/Getty Images)

Keanu Reeves and his co-stars took London by storm on Monday when they hit the red carpet for the premiere of John Wick: Chapter 4.

The actor has starred as the full-throttle franchise’s titular character for almost ten years and speaking to Metro.co.uk on this week’s red carpet, Keanu, 58, revealed exactly what John’s taught him over the years.

Suggesting that the character of John tested his limits, Keanu told us: ‘I try really hard, but with John, you have to try just a little bit harder.’

As for what’s brought him back to the character time and time again, the Matrix actor said: ‘I like his humour, I like his will, I like his grief and it’s really fun to play him in these films, these films are fun’.

The fourth John Wick instalment hits cinemas this month, with Keanu’s Matrix co-star Laurence Fishburne returning as The Bowery King, Ian McShane coming back as Winston, Lance Reddick as Charon and singer Rina Sawayama making her film debut as Akira.

Rina previously raved about working with Keanu, saying: ‘Keanu just has such an ordinariness about him – he’s really down to earth, he’s someone who is so chilled and lovely – just great to hang out with like he’s a family member.’

Speaking to Metro.co.uk on the red carpet, Keanu, 58, revealed exactly what John’s taught him over the years (Picture: Gareth Cattermole/Getty Images)

Keanu joined his co-stars in the capital at the beginning of the week (Picture: PA)

Suggesting that the character of John tested his limits, Keanu told us: ‘I try really hard, but with John, you have to try just a little bit harder’ (Picture: Lionsgate)

‘He just has a great presence, he has a calming presence around him.’

During an interview in March with The Hollywood Reporter, John Wick 4 director and producer Chad Stahelski teased how John would ‘suffer’ in the next release.

‘We keep finding new and interesting ways to have John Wick suffer,’ he said.

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‘That’s where the action comes from. Figure out how to make him suffer, and then design backward.’

As for how many more John Wick films fans can expect – with an Ana de Armas spin-off Ballerina in the pipeline – Keanu said: ‘We just attack one at a time.’

Metro.co.uk caught up with Keanu.