Co-pilot Andreas Lubitz, who is believed to have deliberately crashed the Germanwings plane into the French Alps, had told his pregnant girlfriend Kathrin Goldbach that he had "played away with a flight attendant."
Weeks later he brought the plane down, killing all 150 people onboard, reported The Daily Star.
The news came as investigators demanded to see a footage that surfaced recently and claimed to show the final moments of Flight 9525 before crash.
Twenty-seven-year-old Lubitz underwent treatment for a "serious depressive episode" and took a break from flight training in 2009.
He is also believed to have suffered from "suicidal tendencies" in the past.