WASHINGTON -- President Barack Obama will likely sign his historic health care reform bill on Tuesday in an outdoor ceremony at the White House, his spokesman said.

Obama will invite members of Congress who backed the legislation -- as well as some needy Americans who stand to be helped by the bill -- to the ceremony, which will usher in near universal health coverage for the first time.

"I think each and every member of the House and the Senate that supported health care reform will be invited," Gibbs said of a ceremony that was being planned for the South Lawn of the White House, weather permitting.

The House of Representatives passed the core of Obama's plan late Sunday, along with a package of changes that the Senate must now endorse.

But regardless of the Senate action, the health bill will become the law of the United States as soon as Obama signs it.