In this current climate, where the biggest news in Hollywood is a lawsuit between a director and an actress accused of trampling his film to meet her own needs, the sort of input that Hugh Grant added to both Paddington and Bridget Jones could easily be seen as interference.
In fact, were it not for Heretic – which he did not write, but reportedly added a few lines and “grace notes” of his own – there would be a very strong case for Hugh Grant being the world’s best writer for Hugh Grant.
According to Paddington in Peru’s director, Hugh Grant wrote much of it himself.
So Hugh Grant went away and wrote his own scenes, which were subsequently “infused” into film.
Without wanting to sound like a teacher, if he could apply himself to writing, or even co-writing, something longer form – something that understands his voice and point of view, and melds it to a decent plot – then there’s every chance it would be a big success.