Just as President Barack Obama was promising Americans that his health-care plan would lower premiums, the controversial adviser and architect of ObamaCare was privately warning the state of Wisconsin that the new law would actually increase costs for average citizens, reported The Washington Times.

Now that adviser Jonathan Gruber - the same man who recently referred to Americans as "stupid" - has agreed to testify before a House panel next month regarding the perceived deceptions surrounding ObamaCare's passage and implementation.

According to internal documents examined by The Washington Times, when Gruber was contracted by former Democratic Wisconsin Gov. Jim Doyle in 2010 to conduct an analysis on how health-care reform would affect the state, Gruber predicted "about 90 percent of individuals without employer-sponsored or public insurance would see their premiums spike by an average of 41 percent."

Gruber also theorized that 53 percent of people insured by companies with fewer than 50 employees would see premiums rise by an average of 15 percent, even after subsidies, according to The Times.

Gruber's study was published in 2011, and in 2012, Obama proceeded to campaign on his promise that insurance premiums would decrease under his new legislation.

"You should know that once we have fully implemented, you're going to be able to buy insurance through a pool so that you can get the same good rates as a group that if you're an employee at a big company you can get right now - which means your premiums will go down," Obama said during a campaign speech in Cincinnati, Ohio, in July 2012.

Along with Gruber, Obama administration official Marilyn Tavenner was also called to testify in front of the House Oversight and Government Reform Committee, which will meet on Dec. 9. Tavenner was under the spotlight recently for citing inflated health-care enrollment figures.

Committee Chairman Darrell Issa, R-Calif. claims the hearing is necessary due to "repeated transparency failures and outright deceptions" revolving around the law's implementation.

Gruber will face questioning regarding a number of speeches given since 2010, which blame the Obama administration for intentionally misleading the public and obscuring details of ObamaCare in order to guarantee its passage, reported The Hill.

"The American people deserve honesty, transparency and respect from those who forced the federal government into their health-care," Issa said in a statement released last week. "I expect Mr. Gruber and Administrator Tavenner to testify publicly next month about the arrogance and deceptions surrounding the passage and implementation of Obamacare."