Actor Rupert Grint says kissing his "Harry Potter" co-star Emma Watson was "unnatural" because she's like a sister to him

"It seemed like the most unnatural thing to do, to kiss this person I'd known since she was nine. It took a while to get into it and put our friendship aside. It's quite full-on, a proper snog. We're soaking wet as well - they dumped gallons of water on us and then we just went for it. We laughed a lot and it took us a while to concentrate. We did it about four times," contactmusic.com quoted him as saying.