The Blink-182 star and reality star Kourtney made their relationship Instagram official in February (21), and have been inseparable ever since. So when it came to celebrating the birthday of Penelope - Kourtney's eldest daughter with ex Scott Disick - Travis pulled out all the stops.
The musician shared a video of Penelope playing his set of drums to his Instagram story, before Kourtney shared images and video clips of her nine-year-old sitting at a pink kit with her name written on the bass drum.
"My birthday girl! My favourite girl in the entire world I am so happy and proud to be your mommy. I can not believe that you are 9. My life is sooooo much better because of you," Kourtney wrote.
In the videos, Travis was seen giving Penelope some pointers on the kit as she concentrated hard on her stick work.
Other relatives to wish Penelope a happy birthday included her grandmother Kris Jenner, who shared a slideshow of pictures of her "cutie pie granddaughter" on her Instagram page and wrote, "You are the brightest light, the smartest girl, the most amazing chef, an incredible musician, the most creative at planning special events and surprises, the most thoughtful granddaughter, amazing daughter, sister, cousin and niece and make every single day I am with you very special!"
Penelope's dad Scott and his girlfriend Amelia Hamlin also paid tribute to the little girl on her big day.