If you are a *G and fly TK domestically from IST, you will relax at the domestic lounge before boarding.
When they are ready to board, they will make an announcement.
You just go to the "lounge gate" for a bus.
The bus will take you directly to the lower level of the gate bridge.
Once you go upstairs, you will be already in the gate bridge and you don't even need to see the gate agent.
It is so cool....
It was an amazing service that I got as a *G.
BTW, I also got opup on that flight as *G.