Will Smith thanks Jackie Chan for helping 'raise' son Jaden

American actor Will Smith (left) said Jackie Chan left an "eternal impact" on his family. Photo: Will Smith/Instagram

American actor Will Smith has expressed gratitude towards action star Jackie Chan for helping to "raise" his youngest son Jaden.

In celebration of the Hong Kong actor's milestone 70th birthday, Smith posted several snaps of Jaden and Chan taken from the 2010 remake of The Karate Kid.