It's been 13 years since Love Actually premiered, but Olivia Olson clearly remembers shooting a scene pivotal for both her on-screen character and off-screen self.Spoiler alert, in case you haven't seen this holiday staple : Near the end of the film, Olson gives her co-star, Thomas Brodie-Sangster , a kiss on the cheek."It was my first kiss and on-screen kiss too," she told E! News . "I was really nervous because I kind of had a crush on Thomas back in the day and I was also worried, because I was taller than him if it was going to look weird."Olson's off-screen butterflies may surprise those familiar with the Christmas tearjerker . Throughout the film, Brodie-Sangster's character, Sam, crushes hard on his classmate and talent-show star, Joanna, played by Benson. But Sam and Joanna get a happy ending when Sam rushes to the airport to tell her goodbye and Joanna returns the gesture with that adorable kiss.Grown-up Olson now voices Adventure Time's Marceline the Vampire Queen. Game of Thrones fans can also spot Brodie-Sangster's baby face in his guest-starring role as Jojen Reed.