B767 Captain reported diverting after a fuel imbalance and fuel leak were detected resulting in a diversion.

Narrative

Deiced in ZZZ; about two hours into flight received a fuel config annunciation. Ran QRC; feeding out of center tanks at the time. Fuel flows even. Fuel imbalance was 1;600 lbs. between main fuel tanks; checklist had us balance. I then contacted Maintenance Control and Dispatch via SATCOM. Decision was to continue and monitor. As a precaution reviewed fuel leak procedure. Woke the Relief Officer and had him check wings and engine. Fluid was streaming out of spoiler area along whole left wing while right wing was dry. At first we thought deice fluid but with the aforementioned fuel configuration and imbalance beginning again we chose to divert to ZZZ1 after consulting First Officers and Dispatch and Maintenance Control via SATCOM a second time. Ran diversion guide and fuel leak procedure. [Requested priority handling] and landed uneventfully in ZZZ1. Stopped on taxiway and had Operations look for fuel leak prior to taxiing to gate. Parked at gate and handled passengers and contacted Chief Pilot. Fuel imbalance at shutdown was 1;000 lbs with the left wing low.