Both Grint and Watson have been acting together in the 'Harry Potter' series, with the first having been filmed seven years ago. The kiss that they have to share is in the final flick of the series, Harry Potter and the Deathly Hallows.
"The kiss will be quite uncomfortable," the Sun quoted him as saying. "Emma''s like a sister to me so it''s going to be, like, really, really weird," he added.
'Harry Potter and the Deathly Hallows: Part 1' is not due for release until November 2010.