The actors play detectives Alec Hardy and Ellie Miller in the hit ITV mystery series and said they had no problem in keeping schtum about the killer’s identity in the first series, and about the storyline in the upcoming series two.
Former Doctor Who star David said: “I think it frustrates those around you, but I am well practised at not giving anything away; withholding everything.
“I quite like being the holder of secrets. I get frustrated if I’m the one that doesn’t know them, but happy to be in the slightly superior position of knowing what comes next…”
Olivia added: “We had each other if we needed to talk about it. I did get a lot of texts and emails from close friends and family, asking me who did it, and I quite enjoyed the power of saying no to them all.”
Broadchurch returns to ITV on Monday, January 5, 9.00pm.