"interested in watching" is correct and can be used in written English.
For example: My family is interested in watching a movie together tonight.
Doing this shows that you're interested in him, even if you're not interested in watching pro wrestling.
He is interested in watching his investment".
He wasn't even interested in watching his beloved Rangers.
Asked if he was interested in watching events unfolding in Baltimore, Damon shook his head.
The Kings were interested in watching how women from different generations would interact.
Not everyone is a speed solver, and not everyone is interested in watching people solve puzzles.
Their are four games that I would be interested in watching in their entirety.
Aviation professionals are not the only people interested in watching the workings of busy airports.
But that doesn't mean that women aren't interested in watching and thinking about these issues.
That's at least two streams per every person interested in watching that film.
"We're not interested in watching any more TV," Mr. Mackell said.
