Sen. Arlen Specter (D-Pa.) said on Wednesday that he would personally convince President Obama to back the public health insurance plan ad part of healthcare reform legislation. 

Specter made his comments ahead of the president's address before a joint session of Congress tonight in which he plans to renew the push to pass a sweeping health reform bill.

The Republican-turned-Democrat tweeted upon his return to Washington:

This U.S. Senator is going to tell him (the President) emphatically that we need the public option. http://tinyurl.com/kwykdh

Specter also made comments at a rally outside Philadelphia's 30th Street Station just before he departed for DC.

"I think it highly unlikely that President Obama's going to say the public option's not viable," he said to members of Heath Care for America Now, a group of healthcare activists and union members.

"I think the president may say that he wants to know what congress thinks under our constitutional system and this member of congress, this united states senator is going to tell him emphatically that we need the public option," he added.