The parts – Merlin and Guinevere – eventually went to Colin Morgan and Angel Coulby, freeing up Smith and Gillan to join 2010’s new Tardis team instead – but to mark the 10th anniversary of Merlin’s first episode, we caught up with some of the show’s creative team who told us the behind-the-scenes story of Smith’s near-involvement.
“Casting Merlin was really really hard because you needed to find an actor who had a really big, broad playing range, but also could handle the fact that it’s not naturalistic drama,” Johnny Capps, the co-creator and executive producer of the BBC fantasy series, tells RadioTimes.com in our in-depth feature on the making of Merlin, which will be available to read this weekend.
“So you couldn’t have an actor who was just going to play it in an incredibly earnest, real way. You wanted somebody that could find the truth, but also find the truth as it exists in that kind of fantasy world.”
And on the final shortlist for that part alongside Colin Morgan? Matt Smith, who apparently got down to the last two actors to play the boy wizard.
“Interestingly, in the early days Matt Smith was in the frame for Merlin,” recalls Julian Murphy, another co-creator and executive producer on the magical series.
“I think there’s a certain kind of actor who has the lightness and skill to play that sort of family drama, and I think both Colin Morgan and Matt Smith are that kind of actor. It’s a mercurial quality. And they’re light on their feet. That’s the skill they had.”
However, in the end Colin Morgan clinched it for one simple reason – the casting team felt like the younger Morgan would be better suited to play the adolescent wizard than Smith.
“We just felt that he was too old – not that he wasn’t great,” Murphy said. “And he was too old, really.”
“There were lots of really interesting actors on the shortlist,” added Capps. “And we thought Matt was absolutely brilliant, but Colin just had that quality, he just had the right quality.”
For his part, Smith remembers the experience fondly.
“The first time we [Smith and Gillan] ever met was in an audition for something else, and we got down to the last two for a show, and then we got Doctor Who,” Smith told an audience at the Wizard World con in 2016, “and that show was Merlin.”
“And at the time I remember thinking ‘that would have been good’, her as Guinevere and me as Merlin, then I got the Doctor.”
“That’s not to diminish the quality of Merlin. Merlin’s fantastic and Colin is a brilliant, brilliant actor. But it’s just funny, me and Karen often say ‘oh, you know…’”
And who knows? Maybe in another world, Colin Morgan would be cheerfully reminiscing about his own time starring as the Eleventh Doctor. What might have been…
Merlin is streaming on Netflix now, and Doctor Who returns to BBC1 on Sunday 7th October