Instead, he joked about being "in talks" with Abrams to play a lightsaber in the film, and otherwise didn't really address the question. That seemed like just a guy having some fun with a dumb question from reporters at the time--but now that he's rumored to be in the movie, it seems equally possible he was avoiding the question.
“I’ve already asked him if I can be a lightsaber and we’re in talks – about whirring sounds and the rates for the lights and everything,” Cumerbatch said at the time. “I thought, ‘Yeah, I grew up with them,’ and I just looked recently at when they were released and now I’m like, ‘No, I didn’t grow up with them, I was born with them.’ They were a huge part of my background, and my upbringing. I was much more connected to [Star Wars] as a kid, in the way that a lot of kids are because it’s immediate storytelling, very simple – a beautifully, outrageously simple narrative in a way – and a wonderful three-act melodrama, opera. And I loved them. I really, really loved those films and I always wanted to be Han Solo. Everything Harrison Ford did I just thought was the coolest thing ever – Raiders Of The Lost Ark was very much my upbringing as well.”