United Kingdom, Jan. 16 -- Channing Tatum "peed on" Amanda Seyfried's leg and then "ran away" while they were filming Dear John.

The 40-year-old actress has opened up about working with Tatum, 45, on their 2010 romance movie and she revealed the shoot was full of laughs as the pair "effed with each other" throughout filming - and Seyfried recalled one particular prank on a beach which filled her with horror.

She told Deadline.com: "He and I effed with each other the entire movie in a super, super fun way. He's very, very funny, and we had a great time.

"He peed on my leg once, without me knowing. He peed on my leg on the beach, and I didn't realize at first, and then I was like: 'Oh, that's why he's standing so close to me.'

"There wa...