Fifteen or so years ago, Andy Newbery was working as a TV runner behind the scenes on Doctor Who in Cardiff.

From getting the coffees to running errands, he did the basic jobs that help a drama production to run smoothly.

Now, he's just directed the third series of the Netflix sensation Heartstopper, taking over from the Welsh director Euros Lyn who directed the first two series, and who Andy once worked for.

"Weirdly for me, it's kind of been a bit of a full circle moment doing this with Euros... because I remember plugging him for information about how to get into directing," Andy told Lucy Owen on BBC Radio Wales.

"So the fact that I'm here now, able to pick up the reins on series three, from a show that he's established so beautifully is, for me, a really special thing."

Andy, who is learning to speak Welsh, was born in Hampshire but has regularly worked in Wales, directing dramas such as Hidden and Keeping Faith for BBC Wales and Pobol y Cwm on S4C.

More recently, he directed episodes of Shetland for BBC One.

But Heartstopper seems particularly close to his heart.

Based on the graphic novels by Alice Oseman, the show has been praised for shining a light on the positive elements of growing up as part of the LGBTQ+ community.

"It doesn't shy away from those darker aspects of teenage life and those mental health struggles and things like that, and it isn't afraid to go there," said Andy.

"But what's so great about it, I think, is that no matter how deep you are in it, it always feels like there's a way out, and always feels like pointing towards hope and the positive, and shows that you can get out of these things if you need to."

The series sees a group of friends dealing with transphobia and mental health struggles.

"Throughout series two, we've started to look a little bit at some of Charlie's mental health struggles... so that's very much the focus for series three, Nick coming to realise how serious Charlie's eating disorder is. Charlie's feelings of shame and guilt that go around with that, not wanting to admit it to himself, let alone to anybody else," he said.

"So it definitely feels like there's a sort of growing up and a slightly more mature thing going on in this series, and it all gets a little bit deeper and darker for the gang."

Yasmin Finney's character, Elle, who is transgender, is shown starting a sexual relationship with her boyfriend Tao, played by William Gao.

"A lot of the couples want to physically take their relationship to the next stage, and it's how you navigate that for yourself, but also within a couple," said Andy.

"It's all done very beautifully."

Tobie Donovan's character Isaac is asexual, another topic few dramas have explored.

The diversity of the characters has earned the series legions of devoted fans and Andy said he felt a responsibility taking over as director.

He added: "When you join a show at series three, you want to keep all the elements of it that people love.

"But also you want to put your stamp on it... and I kind of wanted to make sure that the show had its own identity, and does feel like it's kind of growing up and maturing with the characters and with the stories."

Andy is now married and he and his husband are expecting their second child with a surrogate next month.

He said he understood the challenges that can be faced by young people as they come to terms with their sexuality and identity.

"It's the one thing I thought when I first watched Heartstopper, and I've heard it many, many times since, especially from people sort of my age really, about how they wish they'd had a show like this when they were growing up," he said.

"Just knowing that there are other people out there, that queer people exist, and that queer love is possible, and family life within that sort of relationship is possible.

"Hopefully, shows like this will make it easier for the next generation coming through... to hopefully accept themselves a bit more easily and a bit quicker, and maybe some of that shame won't exist in the same way like it did for a lot of us."