The Social Network star embarked on the ambitious journey across America, known as 4k to Hardway, last year (14), shunning luxury hotels to camp in the wilderness, while taking in the scenery as they travelled off the beaten path from California to Florida.

However, Hammer admits they worried they had taken on more than they could handle on numerous occasions, especially when they thought they might actually die in the desert.

He explains, "Things got weird. I mean, you've got a group of guys crossing the country, staying in the middle of nowhere.

"We had some close calls... like, at one point, we stayed outside of Yuma, Arizona and we were like, 'OK, we've got to get from Yuma to Phoenix, but there's no main roads, except for an interstate (highway)...' Everyone pulls out Google maps (on their phones)... and they go, 'You know, it looks like all desert from here to Phoenix, but it looks like there are roads. It doesn't say roads (sic), but it looks like there's trails. I think we can make it.'

"We get off the pavement and it's like a dirt road, it's hardpacked... Everyone's like, 'Yeah, this is the adventure, we're owning this...!' Then all of a sudden, the road gets so soft, you can't sit on (your bike), you have to walk, next to your Vespa, as you're pushing it up a dune..."

Luckily, a law enforcement official spotted Hammer and his crew veering close to the U.S./Mexican border and stopped them before they could land themselves in more trouble.

Hammer continues, "We thought we were gonna die out there at one point, until... this truck... comes flying at us out of the middle of nowhere. We're like, 'Oh my God, it's the border patrol. What have we done?'.

"He comes up and basically goes, 'What the hell are you guys doing?' We go, 'Sir, we're crossing the country on Vespas...

He looks it up... and he goes, 'You guys are crazy. What the hell are you doing in the desert...? Man, I'm really glad I stopped you 'cause... you see that hill right there...? That's Mexico and if you would have gotten any closer, I wouldn't have been able to let you come back.'"

The border patrol agent subsequently helped guide the group out of the desert and get them back on the road.