Jason Segel was so desperate for a treat while embarking on a drastic diet for The Five-Year Engagement, he ate a burger he'd dropped on the floor of a taxi.

The Muppets star slimmed down for the romantic comedy but he found the regime hard to handle and one night broke his vow to avoid calorific meals.

Segel's desire for fast food drove him to extreme lengths, and he was happy to shun hygiene for a fatty fix.

He tells Extra, "They put me on a very strict diet and I had one very dark night. I take a taxi to this diner that closes at midnight and I get a burger and I'm like, 'I'm gonna eat this burger'.

"And we're driving in the taxi and we went over a speed bump and the burger fell onto the floor of the taxi and just disassembled and I just put it back together, I picked off the hair... and then I just ate it."