B747 Captain reported taxiing into the gate a helicopter crossed over the wing resulting in a critical ground conflict event.

Narrative

Upon arrival into ZZZ while taxiing into our gate XX we were taxiing east on taxiway 1. When we passed the general aviation ramp a Robinson R44 was given clearance to taxi behind us to his tour pickup location just east of our ramp. We continued our taxi not knowing where he was as he was behind us. When we reached out gate XX and I began my 90 degree turn in the marshaller stopped me and all ramp personnel and wing walkers crossed their wands to stop. As I stopped the FO and I watched the helicopter come over our right wing and hover down to his parking spot. He couldnt have been more than 40 feet off the ground and had to have come right over the wing as 747s blocked any other route as they were parked in spots X Y Z etc. If the ground personnel had not gotten me stopped the tail and/or fuselage could have been impacted by the operators carelessness. Also boosting engines 3 and/or 4 as I made the turn would have created jetblast that could have led to catastrophic circumstances for the small helicopter.The careless and reckless operation by this pilot was uncalled for and probably got him to his spot 30 seconds earlier. Also he was given clearance to taxi on 1 taxiway behind me to his spot by ground. Not cleared to go airborne by tower.Our ground personnel did a great job seeing the threat and getting me stopped. Absolutely no need for this carelessness.I called ground after block in and got an ops number to call. I discussed the issue with the ops tower guy and he agreed and filed a report on towers end.This is not the first time this has happened to me in ZZZ. 3 months ago the same operator came over my left wing to take a tour airborne while I taxiied west on 1 after landing long on XXR. This was less of an issue because he had been cleared to takeoff but he still could not wait 10 seconds for me to pass and went right over my wing which still had unsafe consequences if engines were boosted etc.