pRupert Grint says he and director M Night Shyamalan have been friends for almost 20 years, since the director almost made a Harry Potter movie.ppThe star has now worked with Shyamalan on several occasions, appearing in new thriller Knock at the Cabin as well as his role in Shyamalan's mysterious TV series Servant.ppKnock at the Cabin is in UK cinemas from 3 February.