HBO is defending the accuracy of “Game Change,” its upcoming movie about the McCain-Palin campaign in 2008, in the face of claims by Palin aides that the movie contains fictitious situations.

Noting the “noise about the film,” HBO exec VP Quentin Schaffer said that “much of it has come from several Palin aides trying to discredit it even though they haven’t yet seen it.”

“HBO has a long track record of producing fact-based dramas, going to great lengths to get the story right,” he wrote.

Schaffer noted that Mark Halperin and John Heilemann, authors of the book on which the project was based, served as consultants and checked “every draft of the script to ensure its historical accuracy and throroughness.” “When their book came out in 2010, it went unchallenged and unrefuted by the Palin camp,” he wrote.

He also said that the screenwriter, Danny Strong, spoke to 25 people “intimately involved in the campaign,” including “the most senior advisers.” Palin and McCain declined to talk to him, and also declined an offer to see the finished movie. Other sources included Palin’s own book, “Going Rogue,” and Palin’s deputy chief of staff during the 2008 campaign, Chris Edwards, served as technical adviser and ‘was there for many of the scenes in the film to ensure its accuracy.”

“The result is a balanced portrayal of the McCain-Palin campaign,” Schaffer wrote.

Meanwhile, Bristol Palin has landed a new reality show, this time with Lifetime. The title: “Bristol Palin: Life’s a Tripp.”