Steve Schwarzman, chairman and CEO of Blackstone, calls the tax reform working its way through Congress a "game changer."

The billionaire former advisor to President Donald Trump as part of his policy forum, told CNBC's "Halftime Report" on Tuesday that the bill was "actually sort of a game changer because there has been enormous frustration in terms of getting legislation passed."

Sure the tax plan isn't a love letter to private equity, he acknowledged. The bill proposes to eliminate the deductibility of interest, something Schwarzman said would be a slight negative for private equity firms, which buy companies using financing.

It also proposes that ordinary income tax be applied to investments of fewer than three years, a longer timeline than the one year threshold currently applied, something that is also not a positive for his firm, he said.

Still, passage of the tax plan would be a sign of progress during a year in which Trump struggled to push his agenda through Congress, losing out on health-care reform after multiple attempts. Schwarzman led the president's policy forum, which disbanded this summer as CEOs revolted against Trump's comments in which he failed to condemn violence at a white nationalist rally.

Tax reform is seen as a critical goal of Trump's first year in office.

Schwarzman told CNBC on Tuesday: "This is a whopper. There is no doubt about it in terms of its impact, scale and the fact that many people thought that this wouldn't work. It seems at this point a pretty good shot that this is going to get resolved before Christmas."