Akshay Kumar wasn't the first choice for Toilet
The producer, Neeraj Pandey was very clear that he wanted a younger actor and Akshay would not suit the role at all.;

Did you know that Akshay Kumar was not the first choice for the film Toilet Ek Prem Katha? The producer, Neeraj Pandey was very clear that he wanted a younger actor and Akshay would not suit the role at all.
The film’s director Shree Narayan Singh too agreed with the producer, because Pandey was clear that the soon-to-be 50-year-old Akshay would look mismatched when it came to wooing a girl and getting married to her. Akshay has also been doing a lot of realistic cinema, hence would not fit the role.
A few younger actors were then considered in the preliminary meetings, but nothing worked. In the meantime, the scriptwriters re-wrote the film and thus adapting it to accommodate Akshay, much to the delight of the makers.
In a sense, Toilet was rebuilt for Akshay to fit in and that’s what convinced Neeraj Pandey that Khiladi Kumar was indeed the right face.
— Sanskriti Media