Light aircraft pilot reported a near-collision with another light aircraft on a taxiway at VNY airport.

Narrative

Incident occurred during taxi out. The pilot of our aircraft; on a personal sight-seeing flight; taxied from the VNY 'Prop Park' area via A2. We checked in with Van Nuys Ground at 'Checkpoint 1' which is short of Taxiway A in a non-movement area. Ground issued an instruction to pass behind two aircraft taxiing northbound on A to runway 16R via A; C. We requested an intersection departure from Taxiway D; which was straight ahead; in order to remain clear off the building congestion of jet traffic at the full length.Ground issued us instructions to pass behind the second jet and taxi to 16R via A; D. We correctly identified the second jet and taxied short of the runway on D without issue. At this point I identified a [high-wing light aircraft] in front of us; known to me to be a flight training aircraft. They had made the left turn onto A and were behind two business jets and unable to access the large run up area.We became preoccupied with a departure and takeoff briefing followed by an engine run up. During the run up; I noticed the [other aircraft] from earlier passing off our left and accessing runway 16R at D; a taxiway we currently were occupying. The pilot flying and I reacted with shock and the pilot flying stood on our brakes; idled the engine and we braced for potential impact. We were on the centerline of D and at the hold short bars. The [other aircraft] appeared to pass us with its left main gear nearly hitting the edge lights; and its high wing passed within 2 feet of our low wing with the [other aircraft's] wing strut coming imperceptibly close to our wing edge. It was extremely close; and I cannot fathom why the aircraft would do that.As we were preoccupied and only listening for our call sign; we did not hear what the instruction to the [other aircraft] was and I do not know if they were cleared to make this maneuver by ATC or did so on their own.