MTV has reported that the 'Teenage Dream' sensation broke down in one of the scenes of her new concert movie, 'Part Of Me', while talking about her relationship with British funnyman Russell Brand and explained that she put her all into the commitment:

"I have that same belief system with everything, from career to my life to my personal life, everything. And I will do everything it takes to not fail. And I did everything it took, but it still failed."

"I thought to myself, 'When I find that person that's going to be my life partner, I won't ever have to choose [between the partner and my career]. They won't be threatened or have weird motives.' Then I started to realise, that's not true."

The movie's official premiere will be held tonight (June 26) in Los Angeles and it will hit cinemas in the UK from July 5.