Kevin Costner’s commitment to ‘Horizon: An American Saga’ has “gone pretty deep”. The 69-year-old actor has committed millions of his own fortune to make the four-part Western saga, and Kevin is happy to pursue his dream, in spite of the cost. Asked about reports that he’s mortgaged a house in order to make the series, Kevin told ‘Extra’: “More than that. It’s gone pretty deep.” Despite this, Kevin has tried not to dwell too much on the financial aspects of the project. The actor – who stars in and directs the series – explained: “You have to know what you’re doing and that’s what you’re doing…