President Obama, following through on his vow to sidestep Congress, will announce in a prime time TV speech Thursday the executive actions he will take to change U.S. immigration law.

Obama will make his announcement, expected to protect roughly 5 million illegal immigrants from deportation, from the White House at 8 p.m. EST.

The president will go ahead with his plan despite widespread opposition from Capitol Hill Republicans, who have asked him to wait until next year when the GOP controls the House and Senate to try to reform the country’s broken immigration system.

Obama is also under intense pressure from Hispanics and much of his liberal base to act now, after promising to act by September, then disappointing them by waiting until after the midterms.

Immigration lawyer Margaret Wong released a statement saying that she had been invited to the White House for a holiday party Wednesday night and that Obama had told her "I had promised. I had promised."

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"He was actually very proud that he's been able to keep his word," Wong said. 

At least some of the estimated 5 million illegal immigrants who would be spared from deportation also are expected to be made eligible for work permits. But the eligible immigrants would not be entitled to federal benefits -- including health care tax credits -- under the plan, administration officials said Wednesday.

Late Wednesday, the United Farm Workers announced that Obama had told union President Arturo Rodriguez that at least 250,000 unionized farm workers would be eligible for deportation relief, with at least half that eligible number based in California.

The president in 2012 used executive action to delay deportation for some of the millions of young people brought to the U.S. illegally by their parents.

House Speaker John Boehner has warned Obama that taking executive action on the immigration issue before January would be tantamount to "playing with fire."

And on Wednesday, before the announcement, Boehner aide Michael Steel referred to the president as “Emperor Obama,” referring to his attempt to govern alone.

The Democrat-controlled Senate last year passed bipartisan, comprehensive immigration-reform legislation. However, the GOP-controlled House has not passed such a bill.

“We've been waiting for a year for House Republicans to come to a vote,” White House Press Secretary Josh Earnest said Wednesday. “We're confident it would pass with bipartisan support.”

He also said the president chose to act because the House has indicated it will not address immigration reform in the next Congress.

Congressional Republicans are already working on a strategy to stop Obama from using executive action, including a plan to submit a temporary spending bill that would cut any funding for related efforts -- like issuing Social Security cards for those to be protected under the Obama change.

The federal government technically runs out of money by December 11. So the president and Congress failing to promptly reach a budget deal could result in a partial government shutdown. However, Republicans have said they do not intend to submit a budget that Obama would veto and result in a shutdown.

"What I'm going to be laying out is the things that I can do with my lawful authority as president to make the system better, even as I continue to work with Congress and encourage them to get a bipartisan, comprehensive bill that can solve the entire problem," Obama said in a video posted on Facebook on Wednesday.

Obama is scheduled to host a White House dinner before the speech for 18 congressional Democrats to talk about immigration and other second-term priorities, then travel to Las Vegas to tout his changes.

Senate Majority Leader Harry Reid is expected to join the president in his home state of Nevada.

Reid said Tuesday that Obama should take executive action as quickly as possible, a shift from last week when he said the president should wait to act until Congress had completed work on the must-pass spending legislation.

"I believe that when the president decides to do his executive order, he should go big, as big as he can," Reid said, adding that he had spoken with Obama on Monday. "I said he should do something as quickly as he can."

However, other Democrats still want Obama to wait on unilateral action for fear such a move will poison spending-bill negotiations.

"I wish he would let the process work for a few months before he did this," said Sen. Jon Tester, D-Montana.

The Associated Press contributed to this report.