Sometimes, a series tends to be defined by the calibre of guest stars it can get.

Like shows such as The Simpsons, who can get anyone they want, you know you have arrived when you get can get the best of the best on your show, especially playing ridiculous characters.

And as such, Peter Kay never fails to disappoint when it comes to guest stars on his hit series Car Share – and fans think last night’s spectacular cameo could have been his best signing yet.

Viewers were left in fits of laughter when a larger than life, drunken, gossiping Irish smurf nabbed a ride home with Peter’s character John, sparking plenty of debate online about who exactly was playing the blue paint smeared passenger.

Many of them thought it was Peter himself under the blue paint, confidently taking to Twitter to share their theory.

One wrong: “Lol, Peter Kay is the smurf.”

Another said: “Is that Peter Kay as the smurf?”

But they were wayyyy off the mark as the identity of the drunk smurf was later revealed to be none other than Game of Thrones star Conleth Hill, better known as the scheming, conniving eunuch Lord Varys.

The Laurence Olivier Award-winning actor, from Northern Ireland, plays John and Kayleigh’s hilariously outspoken colleague Elsie who has dressed up in blue body paint and a wig for their office work party, as though the appearance of John as Harry Potter and Kayleigh as Hagrid just wasn’t enough.

John is forced to drive Elsie home alongside Kayleigh, played by Sian Gibson, but while the pals are singing along to Forever FM and having a great time, John is less than impressed at his unwelcome passenger.

As many have pointed out, who would have thought you would hear the GoT star singing tunelessly along to Loving You by Minnie Riperton as well flirting heavily with Peter’s character John?

Fans absolutely loved the surprise appearance, taking to Twitter in their droves to praise Peter for creating the drunken smurf character, and applaud Conleth for bringing it to life:

In the second series John and Kayleigh have found themselves reluctantly having to make the daily commute to work separately now that Kayleigh has moved in with her sister in Bury.

But John still goes out of his way to give her a lift.

Series two of Peter Kay’s Car Share is on iPlayer now as a box set and it continues on BBC1 on Tuesdays at 9pm.

There are four episodes in this second charming series about the work friends who share a car back and forth to work in a supermarket – and fans are already calling for a third series.