Entertainment Tonight reported the group attended a screening of the new Halle Berry movie Kidnap. Jenner and Scott left the theater in the same car as they tried to avoid paparazzi, according to Hollywood Life.
Jenner celebrated earlier in the night with Khloe, mom Kris Jenner, sisters Kendall Jenner and Kim Kardashian, nephew Saint West and niece Dream Kardashian. She posted a video on Snapchat of her family singing "Happy Birthday."
"Happy birthday my beauty, @kyliejenner! 20 today!!" Kris gushed on Instagram. "I am so proud of the young woman you have become. Kind, generous, hard-working, funny and beautiful inside and out. You are one of a kind, and I'm grateful every day that God gave me you. I love being your mommy!"
"There is so much ahead for you, my angel, and I can't wait to see what your 20s has in store!! I love you more than you will ever know! Mommy xo," she added.
Scott was also present for the surprise birthday party Jenner's family threw Wednesday evening. He and the reality star were first linked in April following Jenner's split from her ex-boyfriend, rapper Tyga.
"Travis is telling friends that he and Kylie are the real deal," a source told Us Weekly in May.