The Australian actor thinks filming 'Liz & Dick' - in which he plays Richard Burton to her Dame Elizabeth Taylor - should have run ''smoother'' and he was frustrated over the time some things took on the TV movie.
He said: ''There were exercises in patience and there were exercises in tolerance. I believe it could have been smoother at times, it could have been a lot smoother at times and we could have got a lot more done on a couple of days, but you get what you're given.
''My focus was whether we could knuckle down and get a film made.
''We certainly took our time in a lot of ways when I would have preferred to be shooting.''
Grant admits the delays to filming left him ''mad'' but he tried to focus on doing the best job he possibly could.
Asked if he got mad, he told 'Access Hollywood': ''Well, you know, yeah. But a part of the job is you're off when you're off, you're on when you're on and you're focused.
''Every single job is an opportunity to get better at my job, I've been doing this for 22 years and all I care about at the end of the day is how well I do my job and how well I serve my audience.''
And while the film has already been widely panned by critics, the 44-year-old actor thinks it is much better than has been reported, thanks to the backstage staff.
He said: ''I'd probably give it a B. Our hair, make-up and wardrobe people did a phenomenal job. They should all be up for awards. The look of the thing is phenomenal.''