A Touch Of Frost (ITV1, tomorrow); 8pm, and Monday 9pm); Jonathan Creek (BBC1, tomorrow,9pm)

AS one old favourite debuts with a new face, another takes his final bow, while a third is up to his same old tricks over the Easter weekend.

If you’ve been living on another planet you might not have heard that Matt Smith is the new Doctor Who. He was seen briefly during the regeneration scene in the New Year, as David Tennant said goodbye as the Time Lord.

Tonight Smith, the 11th Doctor, gets a chance to show what we can expect from him. As the youngest actor to play the iconic role, he has plenty of energy and enthusiasm to remind you of a hyperactive young professor. The tweed jacket and bow tie, the outfit he dons towards the end of the episode, reinforce that idea.

New executive producer and lead writer Steven Moffat eases him into the episode with some crazy comedy as he adapts to his latest face and body.

The new-born Doctor has cravings.

“Can I have an apple?” are his first words after the Tardis crashes into a garden shed in someone’s back garden.

“Who are you?” asks young Amelia, thinking he’s the answer to her prayer to send someone to look into the mysterious crack that’s appeared on her bedroom wall.

“I don’t know yet, I’m still cooking,”

replies the Doctor.

By the end of the episode, he knows exactly who he is and what he’s doing after defeating another bunch of aliens who have taken over humans with the intention of destroying the world.

He’s also asked kissogram Amy Pond (Karen Gillan) out on a date – to be his companion in the newly-refurbished Tardis. That’s only after a spot of worldsaving despite having no Tardis, no sonic screwdriver and having only 20 minutes to do it.

This opening episode, The Eleventh Hour, is a good start to what promises to be yet more entertaining trips through time and space. Yes, we’ll miss Tennant – recently voted the best ever Doctor – but Smith looks likely to give him a good run for his money.

AS Smith makes his first appearance, Detective Inspector Jack Frost makes his last in a two-part finale of A Touch Of Frost on ITV1, although the exact manner of his departure – dead or alive – is unclear.

Two alternative endings have been filmed to keep everyone guessing about his fate in a series that’s been running for nearly 18 years.

The story, If Dogs Run Free, follows Frost’s battle to convict Gerry Berland (Adrian Dunbar), a dangerous criminal masquerading as a successful businessman.

He’s been evading prison for years and, tenacious as ever, Frost is determined to send him down.

The case involves RSPCA officer Christine Moorhead (Phyllis Logan) and as Frost protects her from the harassment of Berland’s thugs, he finds himself falling for her.

The cast includes Niamh Cusack, Leah Bracknell, Simon Shepherd and George Costigan.

Jason admits that saying goodbye to Frost was a highly emotional experience.

“On the final day of filming there were moments in the script when I had to find tears and let’s just say those tears weren’t hard to find,” he says.

“I think everyone on set had the feeling something really special, which had been a big part of all our lives, was finally coming to an end. You’d have needed a heart of stone not to feel emotional.”

BACK for a special one-off episode is illusionist Jonathan Creek, played once more by Alan Davies.

He and intrepid investigator Joey Ross (Sheridan Smith) are called in when a young woman becomes seemingly possessed by the spirit of a Victorian sorceress and is accused of murder.

Davies recalls how he was cast after being invited to the BBC Christmas party by the show’s original producer back in 1995. “They were looking to cast the show, so I hired the dinner suit but the only good coat I had was my duffle coat. So I put that on and I had quite long hair then, so looked out of place,” he says.

“They must have looked and said, ‘that’s the kind of shambling idiot we’re looking for, this socially incompetent fool’.”