Christa B. Allen opens up to ET’s Deidre Behar while promoting ‘Christmas for Keeps,’ airing Dec. 18 at 10 p.m. ET/PT on Hallmark Movies and Mysteries as part of the network's Miracles of Christmas programming event. The actress shares sweet stories about her friendship with Jennifer Garner, after playing the younger version of her in ‘13 Going on 30’ and ‘Ghosts of Girlfriends Past.’ Allen praises Garner’s kindness, and even reveals that it’s because of Garner that Allen landed the role in ‘Ghosts of Girlfriends Past.’ She opens up about posting ‘13 Going on 30’ nostalgia videos on TikTok, just ahead of her own 30th birthday in real life. Plus, Allen shares how she feels about the film’s upcoming 20th anniversary in 2024. With nearly 2 million followers on TikTok, the social media star explains why she’s embraced the platform and how it’s empowered her as a creative content maker. And still, Allen is committed to her craft as an actress, which fans will see in her new holiday project. She reveals why the film feels so special and what all that fake snow used in movies is actually made from!