Newt Gingrich has just been added to the witness list for tomorrow's House hearing on energy and global warming legislation.

Gingrich will appear before a subcommittee hearing immediately follow the testimony of Al Gore and former Sen. John Warner (R-Va.), who are expected to make a bipartisan push for the comprehensive energy legislation introduced by Reps. Henry WaxmanHenry Arnold WaxmanThe Hill's Top Lobbyists 2020 Focus on cabinet nominees' effectiveness and expertise, not just ideology Lobbying groups received millions in PPP loans MORE (D-Calif.) and Ed Markey (D-Mass.). That legislation includes cap-and-trade provisions.

"Some on the majority side believed for the longest time that the former speaker knows a lot about health policy but not so much about energy or the environment," said Lisa Miller, a spokeswoman for Republicans on the committee. "When reminded that he was a former professor of environmental studies and wrote two books, 'Contract with the Earth' and 'Drill Here, Drill Now, Pay Less', they decided to permit him to testify before a subcommittee. It wasn't a bad outcome, even if it took awhile."

Gingrich is a vehement opponent of cap-and-trade. He's also rumored to be considering a Presidential bid in 2012.