The couple celebrated Knox's 8th birthday Tuesday morning at The Griddle Cafe in West Hollywood. The kid's got a major sweet tooth -- we're told he filled up on Oreo-filled pancakes topped with whipped cream and powdered sugar.
While Knox's mom and dad can afford private jets and French castles, they're actually known for being very down to earth parents.
Unclear why twin sis Vivienne wasn't there. Maybe she's more of a lunch person.