Gavin & Stacey's Ruth Jones talks unearthing "mystery" of family history on Who Do You Think You Are?

She had little knowledge about her family history prior to taking part, meaning several of the revelations unearthed came as something of a surprise.

She said: "My journey was focused on my two grandfathers who I never met – I knew a bit about my dad’s father because he died in the late 50s and my dad talked about him a lot – having said that, I thought I’d find out about his military experience in World War 1 but that wasn’t the road we went down and the stuff about the medical aid societies which were the pre-cursor to the NHS, was all news to me!

"My mum’s father was a mystery even to her as he died when she was two. I was really keen to find out about the Welsh speaking element in our family and to go back to a time when Welsh was spoken as a first language in our family."

Asked about whether she was apprehensive about what she might discover, the Gavin & Stacey star said: "I had an open mind really – I think you have to.

"What was great was that during the filming week, from day to day you have no idea what you’re going to learn or where you’re going to go. It’s a proper mystery tour."

The episode, which airs on BBC One tonight, sees Jones discover the story of relatives outside of Wales too, as well as getting to read some of the letters they left behind.

Jones added: "I didn’t know we hailed from New Quay on my mum’s side - or that my paternal grandfather was such a romantic! I got to read some letters from my paternal grandfather to my grandmother and they were so tender and romantic.

"I did wonder if he was looking down, how he’d feel about my reading out his love letters on national television! It was heartwarming to discover how in love my grandparents were though."

Who Do You Think You Are airs Mondays at 9pm on BBC One. Check out what else is on with our TV Guide, or take a look at our new TV shows 2020 page to find out what's airing this autumn and beyond.