After a career playing bubbly, enthusiastic characters in small roles, Melissa McCarthy hit the big time with her Oscar-nominated turn in 2011's Bridesmaids. But she has played essentially the same character in her last three films: as a sociopath in Identity Thief, a cop in The Heat and now a woman on the run in Tammy.

TammyMelissa McCarthy at the premiere of Tammy - photo: Getty 2014, Christopher Polk

All three of these characters begin as out-of-control slobs, overweight and unkempt, impulsive and self-absorbed. And over the course of the film they discover others might like them better if they wore slightly less hideous clothing and combed their hair. Admittedly, McCarthy is great at this kind of role, but the joke is beginning to wear rather thin.

More: How Melissa McCarthy’s Jet Ski Accident Cost 'Tammy' $9,000

The problem is that we know she can be much better than that. Her longest-running TV characters are far more complex: ditsy control freak Sookie St James over seven seasons in Gilmore Girls (2000-2007) and sassy romantic in Mike & Molly (four seasons and counting), for which she won an Emmy. 

But Bridesmaids changed everything, creating McCarthy's alter-ego as an entertaining scene-stealer who might do something outrageously unexpected in any scene. This led to memorable side-characters in films like the The Back-up Plan, Life as We Know It, This is 40 and The Hangover Part III. 

More: Check out clips and the trailer for 'Tammy'

But now that she's made three films centred on her chubby-idiot alter-ego, let's hope she gets back to more interesting characters. If in doubt, take a look at her three roles in The Nines (2007) opposite Ryan Reynolds. She definitely has it in her to be more than a joke.