Criminal cast say it’s “thrilling” to see guest stars like Kit Harington “transform”

Speaking to RadioTimes.com and other press, Criminal's cast of series regulars – Katherine Kelly, Lee Ingleby, Rochenda Sandall and Shubham Saraf – insisted that this year's guests all deliver something that audiences haven't seen from them before.

"Most of our guest actors... they're probably known for a certain character... even perhaps a particular genre as well," said Kelly, returning as Detective Inspector Natalie Hobbs. "[But] there's a lot more flavours in them and they want to show that they can absolutely do that – and all of them really can. I find it really thrilling to watch people transform."

Saraf, who plays Detective Constable Kyle Petit, singled out The Big Bang Theory's Nayyar - who appears in episode four as Sandeep Singh - as the performer who surprised him the most. "I was like, 'woah, this guy's incredible', because the only thing you've seen him in before is so sort stereotypical, and brilliant, in its American sitcom set-piece comedy [style] and this was so different.

"You could see him really relishing it as well. I was just really impressed with his work and, also as a young Indian actor, to just watch him pull out those chops was really inspiring to me."

For Sandall, who stars as Detective Constable Vanessa Warren, it was Harington - taking on his first major TV role since the finale of Game of Thrones - who left her astonished. "Kit Harington gets to play - to put it impolitely - a real d**k, and it was amazing because he's so honourable as Jon Snow, and he's been tied to that piece for so long. I could just see him really embracing it and enjoying it."

Harington was so attached to his role as arrogant businessman Alex Daniels that he even helped put together the character's costume. "He brought his own character socks," revealed Saraf. "Those socks that you see, he picked those out, 'cause he was like, 'those are w**ker banker socks!'."

With a new guest star being rotated for each new episode, the Criminal regulars have noticed that each new performer brings with them a different approach and mood to filming.

"I know every one of our guests has found it a very unique experience," Kelly said. "Every guest, no matter how... well they're all very tremendously experienced, but this is still an experience quite like no other."

"You meet them on the day in the make-up chair," explained Ingleby, back to stare down more suspects as Detective Inspector Paul Ottager. "Initially, you don't want to be to 'Wahey, how ya doing?!' – you need to give them space... especially like say with Kunal, who was playing a very different character. I think he just wanted to keep that slight distance and then as the week went on, once he'd kind of got his big stuff out the way, you could see him relaxing and freeing up."

"Every actor's different in terms of how they personally approach work," echoed Sandall. "And as a team what we tend to do is we come together and assist anybody that comes on, because it is such a tough job that the criminals have to facilitate in such a short amount of time.

"I mean, we film an episode in five days – everybody deserves a pat on the back that's passed through Criminal, especially because they've got that first day at school [feeling] – it's hard to come into a core team that have worked together already for a year. So we just try and assist the vibe that they want, definitely."

Criminal season 2 lands on Netflix on 16th September – check out our lists of the best TV shows on Netflix and the best movies on Netflix, or see what else is on with our TV Guide