It's Tim Kaine. Hillary Clinton says in a text message to supporters that she's picked the Virginia senator to join her on the Democratic ticket as her running mate, reports AP. In the message, Clinton says: "I'm thrilled to tell you this first: I've chosen Sen. Tim Kaine as my running mate." Kaine, 58, is expected to join Clinton at a rally in Florida on Saturday. A favorite since the start of Clinton's search for a running mate, Kaine is a former governor of the battleground state and former mayor of Richmond. Kaine won election to the Senate four years ago after serving as the chairman of the Democratic National Committee. He is not, however, Mr. Charisma. Kaine has referred to himself as "boring," a trait that Clinton acknowledged with a laugh last week in a PBS interview: "I love that about him."