He could recognize that voice anywhere. Spinning around, the Doctor is now face to face with one Captain Jack Harkness and meets him with a wide, toothy smile. There's a tone of relief hidden in that smile, as the Doctor wasn't one to be fond of missing things and having no recollection of possibly being captured and brought here, let alone losing a TARDIS, wasn't welcomed.
"Jack!" He closes the distance between the two and doesn't hesitate to bring him in a hug. Hands are still touching him as he pulls back, "How did we get here?"