Barack Obama has abandoned his more than two-year silent treatment toward "FOX News Sunday," accepting an invitation to appear this week on the national morning talk show.

The Democratic presidential candidate's appearance will end a 772-day record of refusing to sit down for an interview.

FOX News Sunday host Chris Wallace said the decision to launch a "count-up" clock may have helped encourage Obama's decision to be a guest.

"We started the clock a month ago at 730 days. This Sunday it will be up to 772 days and the conversation about Obama coming on got a lot more serious after we started the count down, or the count up," Wallace said.

He added that an Obama campaign aide had called the clock "obnoxious" when it first aired on March 16, 2008.

"It may have been obnoxious but it was also effective," Wallace said.

Last Sunday, the Obama clock was past 765 days, 13 hours, 54 min and 47 seconds by the end of the show. Since then, Obama lost the Pennsylvania primary to Hillary Clinton by 10 points, the first primary to be held since the clock aired. The two candidates face off next in North Carolina and Indiana on May 6.

Wallace said if Obama had won Pennsylvania, he may not have accepted the invitation.

"If he had won he'd probably on a Caribbean island this weekend. The fact that he's going to be on Sunday television and on FOX News may be an indication he figures he has to reach out to working-class Democrats, moderates and conservative Democrats and FOX News is a good place to do it," he said.

Clinton last appeared on "FOX News Sunday" on Feb. 3. Obama will pre-tape his appearance on Saturday from Marion, Ind., to appear on local FOX affiliate stations on Sunday morning.  "FOX News Sunday" airs on FOX News Channel at 2 p.m. ET Sundays.