Widebody Transport
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Clearance
Flight Crew Took Evasive Action
Human Factors
We were facing east on Taxiway X. There was aircraft Z facing us at Y. He was cleared to cross Runway XX at Taxiway Y and we were cleared to cross Runway XX at Taxiway X. There was aircraft Y behind aircraft Z. He made his left turn to cross at Taxiway Y. We aren't sure of his taxi instructions. I was trying to get a little speed to make it over the uphill of crossing Runway XX so I wouldn't have to use excessive power. As I got about 30 degrees into my right turn I realized aircraft Y had turned right onto Runway XX. We were not expecting him to be directly in front of us. We slammed on the brakes and my FO queried Ground Control. It was then that he realized our radio was on the guard frequency and we may not have heard a call from ground. Based on Ground's response to our surprise of aircraft Y in front of us I felt we had not missed anything on ground frequency. We came as close as I would ever want to come to having a taxi incident.We may have missed a call to give way to aircraft Y when our radio was on guard instead of Ground frequency.Since we were in such close proximity to aircraft Y; it might have been better to delay one of our taxi clearances or at least tell one of us to give way in our initial taxi clearance. I'm not sure Ground was aware of our situation.
As the FO; I queried Ground Control as to why the aircraft Y was taxiing in front of us and their response was; 'Sorry about that'. On a side note; I did mention to them that we wanted to make sure we didn't miss any previous information about aircraft Y; but they did not add any more information.
Wide body air carrier flight crew reported an abrupt stop was necessary to avoid a collision on the ramp with another wide body aircraft.