AUSTIN (AP) – Texas Lt. Gov. David Dewhurst has formally launched his expected campaign for the U.S. Senate.

Campaign manager Jim Bognet tells The Associated Press that Dewhurst filed paperwork with the Federal Election Commission and sent a three-minute video to about 500 of his close supporters on Tuesday.

The move thrusts the millionaire businessman into a Republican primary that already has several candidates. All are vying for the seat held by Republican Kay Bailey Hutchison, who is not running for re-election in 2012.

The 65-year-old Dewhurst is widely expected to be willing to spend some of his personal fortune on his campaign.

Dewhurst was elected lieutenant governor in 2002, holding the job that made him the presiding officer over the Republican-controlled state Senate.

(Copyright 2011 by The Associated Press. All Rights Reserved.)