Watch Sam Heughan and Graham McTavish Ride a Tandem Bike on 'Men in Kilts' (Exclusive)

BFFs forever!

Sam Heughan and Graham McTavish are having a grand old time on Men in Kilts.

The Outlander stars hit the road as they explore Scotland's hidden gems and learn the unique history behind the country's most historic sites on Starz's travel show, but the fearsome duo couldn't help but get a little exercise in while seeing the sights. What better way to do that than a tandem bike!

In ET's exclusive sneak peek from Sunday's episode, Heughan and McTavish hop on an '80s tandem bike -- Heughan's idea apparently -- as they cycle down a country road, the lush fields of Scotland on either side.

"This is so pleasant!" Heughan exclaims on the back of the bike, while McTavish doesn't seem too sold on that word as an accurate descriptor for his experience. "It's such an interesting adjective, pleasant. Not one I would use."

McTavish, though, quickly becomes distracted by some fresh blackberries and Heughan tries to steer his friend closer to the side so he can grab some -- to no avail and to McTavish's horror

"This is like my ultimate holiday," McTavish says, prompting Heughan to laugh. "Cycling on a 1980s tandem that is breaking my backside while you stare into my a**." "Yeah, it's remarkable!" Heughan quips.

Here's what the guys are up to in this week's episode: "Scotland's feudal clan system defined the country and still plays a massive part in the modern culture and identity of its people. Sam and Graham set out to discover how they (and their Outlander characters) fit into a system forged through war and peace."

Men in Kilts airs Sundays at 9 p.m. ET/PT on Starz. For more, watch below.

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