'When I take my shirt off, it won't be funny': Is Jason Segel taking weight loss for new film Sex Tape to the extreme?

Much is made of the pressure on Hollywood's leading women to be thin, wrinkle free and generally soothing to the cinema-going retina.
But the men of Tinseltown are not immune to such concerns, even if their stock in trade is humour rather than hunkiness... as Jason Segel is currently illustrating.
The strapping 6ft4 actor, 33, seems to have lost a drastic amount of weight over the summer as he prepares to strip down for his new romantic comedy with Cameron Diaz, 41.

Gaunt: Jason Segel looked worryingly thin as he headed out in Boston on Friday, he's slimmed down Sex Tape with Cameron Diaz which is filming in the city

Muppets star Jason has been open about his desire to lose weight ahead of the movie which pitches him and Diaz together as a newly married couple with a missing sex tape.
 Work on the project started in September and Jason told Us Weekly ahead of filming :  'It is R-rated and I'm not in shape for no reason.'
'This time when I take my shirt off, I've made a promise to myself, it doesn't have to be funny.'

But while the drop in weight seemed to agree with Jason back in July at the CW, CBS and Showtime  Summer TCA party on July 30... it seems to have been taken to the extreme now.

What a difference a few months makes: Jason has lost a lot of weight since the spring , pictured on the right in June

Strapping: Segel (far left) with Josh Radnor and Neil Patrick Harris in How I Met Your Mother

The actor looked worryingly gaunt, with sunken eyes that made his wrinkles look much more pronounced than they should at his youthful age. 
He told Us: 'I've just been living healthy, exercising, eating right - no more midnight pizzas. '
However, despite dating finding love with actress and model Bojana Novakovic, 31, Jason's split with Michelle Williams earlier this year also took it's toll.
A source told Mail Online that the heartbreak diet kickstarted Jason's weight loss back in March.

'They decided the relationship just couldn't work with Michelle in New York and Jason's commitments here but it doesn't mean he wasn't heartbroken,' the source said.

Too extreme? Jason on Friday then back in July when he was just starting to see results

Lost love: Jason and Michelle couldn't make it work

'He discovered he wasn't as hungry as he normally is and that helped him lose weight, then it just became routine.'
Many fans will be concerned with Jason's weight loss, especially given that it's for a romantic comedy.
The star is also wrapping up the last season of How I Met Your Mother, which could prove tricky with his rapidly diminishing frame.