Roland Burris is now officially a U.S. senator.

The Illinois Democrat was sworn-in by Vice President Dick Cheney Thursday at a Capitol Hill ceremony, ending a contentious battle over his legitimacy and making him the lone black member of what has been called the world's most exclusive club.

His new colleagues in the Senate chamber responded with applause.

He takes his Senate seat alongside fellow Democrats who initially turned him away, and who had vowed not to seat anyone appointed by embattled Gov. Rod Blagojevich.

The governor, who's been impeached by state lawmakers, is accused of trying to sell the Senate seat that had been held by President-elect Barack Obama.

Last week, Burris was turned away when other new members were sworn in because he was told his credentials were not in order.

Burris is now being given a polite welcome by Democrats, who say they never had anything against him personally.

Senate leaders are expected to hold a celebratory reception for Burris in the Mansfield Room of the Capitol, the same room where Obama met with Democrats on Tuesday to push his agenda. Sources told FOX News that Obama might even personally call in and congratulate the official who will assume his seat.

FOX News' Trish Turner and The Associated Press contributed to this report.