Daniel Radcliffe has said his What If co-star Zoe Kazan had a message for him on set - which she wrote out across her nipples.
The actors were on a night shoot in a cold lake in Canada for a skinny dipping scene in their new rom com, but Harry Potter star Daniel said it was more fun than it sounded because of Zoe's practical joke.
He said of the shoot: "I've had much worse nude scenes in my life. It was kind of a fun scene because it's about skinny dipping and actually that night, it wasn't warm but it wasn't nearly as cold as I have felt it be in Canada at that time of year, so it could definitely have been a lot worse.
"We had a lot of fun. Zoe wrote me a message on her nipple pasties which said, 'Hi Dan'. It was a concise message. It was fun, it was a good couple of days."
Asked how he responded, Daniel admitted: "I tried to write, 'Hi Zoe' on my bum, but I seem to remember trying to do it in a mirror. My handwriting is not great at the best of times. Trying to do it backwards on the back side of me, it would not have gone well."
But he added of the skill: "Very few people need it, to be fair. There's not a great call in life for being able to write on your bum."
What If stars Daniel and Zoe as best friends who realise they are perfect for each other, except that Zoe's character is already in a relationship.
The film is released in cinemas on August 20.