The Senate’s size will jump to 99 Members on Tuesday when Rep. Kirsten Gillibrand (D-N.Y.) is sworn in to replace now-Secretary of State and former Sen. Hillary Rodham Clinton.

Senate Majority Leader Harry Reid (D-Nev.) announced Monday that Gillibrand’s swearing-in will occur at 12:30 p.m., just before her first Democratic caucus luncheon.

With Gillibrand on board, the only Senate seat that remains unfilled is in Minnesota, where Norm Coleman (R) is battling it out in state court with Democratic challenger Al Franken. Franken holds a 225-vote lead after a state canvassing board recount.