Behind the scenes on this week's Top Gear

How time flies. Can you believe that we're on episode four of series 21 already? And don't worry if you missed episode one, two or three, just click the blue words to catch up.

So, what's coming up this week? Lots of cars, that's what. And for the first time in this run, only a few spots of rain.

James heads out on track in a pack of Caterhams, Jeremy snakes through the Italian Alps in the delicious coachbuilt Disco Volante, and Richard heads to the desert in a big Mercedes with more wheels than strictly necessary.

And the star filing the front seat in our reasonably priced car this week is posh funnyman Jack Whitehall. We can honestly say we've never seen someone so terrified behind the wheel of our Astra Techline. But then, to be fair to him, he doesn't have a driving licence.

Oh yes, and Jeremy has a new theory which he tests in the studio in spectacular style. We can't say much about it now, but it's definitely worth a watch on Sunday's show.

As ever, it's at the same place at the same time: this Sunday, 8pm on BBC Two. Here's some pictures to get you in the mood.

Pictures: Mark Yeoman

Jeremy's getting very good at air guitar. This is the second solo from The Lamb Lies Down On Broadway

League of Their Own panelist and driving licence-less Jack Whitehall readies himself for the Astra Techline

It appears there's still some work to be done on the next generation Bentley Continental

James and Richard didn't approve of the Quorn Toad In The Hole on the menu this week

"I'm sorry. Your name's not down, you're not coming in"

It was a double rollover for Stig this week. He got to power lap not one...

...but two Caterhams. Can you guess which one was quicker?

Tune in on Sunday to hear Jack's story about massaging not one, but two dwarves heads at the same time

And yes, that is the look of sheer terror adorning Jack's face