updated 07/08/2013 AT 5:00 PM ET
•originally published 07/08/2013 AT 6:30 PM ET
Jaden Smith just got a very sweet, very public birthday wish.
Jenner, 15, whose half-sister is new mom Kim Kardashian, shyly looks away from Smith in the photo and, in the caption, writes about Smith’s understanding nature and their shared sense of humor.
“You understand me like not many do and you always know the right time to make me laugh,” she said.
Jenner also mentions Smith’s good manners, which his parents Will Smith and Jada Pinkett Smith may be happy to hear. Jenner said Smith never fails to “open the door on my every entrance.”
The Karate Kid star has been known to say a nice thing or two about Jenner, causing speculation that the two are more than just friends. Smith has not commented on whether the two are a couple.