The star of the seaside cafe comedy reveals five secrets from the set

1 I got into the character of Koji, an African doctor seeking asylum in the UK, by thinking about my parents, who were Nigerian – I can hear my father in him. But I based Koji mostly on a Nigerian film director I met who had this British essence about him. He embraced his country’s colonial influence, and you see it in Koji’s eloquence, nice suit and snobbery.

2 I hadn’t met Brenda Blethyn, who plays Kate, before, but I was a big fan. She has an inner clown. I don’t normally laugh during scenes, but Brenda made me do so often. We had fun between filming – Brenda and Blake Harrison [Kate’s nephew Medium] would show off their tap dancing, Brenda and I sang songs from old musicals and we’d laugh at internet videos of talking dogs.

3 Our outside shots were filmed in Herne Bay, Kent. People would wave and shout at Brenda, who lives not too far away. On my afternoon off I went to a spa and big burly men in the sauna were saying, ‘Aren’t you shooting that show with Brenda?’, and asking questions, which was funny.

4 For most of the rest of the series we were at Elstree Studios, where I worked for three years as surgeon Antoine in Holby City. It was like going home, and I bumped into old friends from the cast and crew. Some of them came to see us filming, which was really special.

5 At Elstree we filmed in front of a live audience and we were lucky in that the show’s co-writer Andy Hamilton was our warm-up guy – he’s very entertaining. But one night he introduced Blake as ‘Steve’ by mistake – and Blake’s mother was in the audience. Andy got a lot of stick for that!

KATE & KOJI Wednesday, 8pm, ITV Kate with Koji