Hey Fred, get your own supporters!

Fred Thompson -- Law & Order star, former Tennessee senator, and likely late entry into the Republican presidential contest -- has just poached one of Mitt Romney's key conservative supporters in Congress.

US Representative Marsha Blackburn of Tennessee, who's been with Romney since January, announced today that she is jumping ship and will now back Thompson if he runs.

Blackburn, as reported by The Hotline, had said this to say in a statement: "Fred Thompson is a man of uncommon talent, character and judgment. He is a proven statesman and public servant. He is the right person for these challenging times ... I sincerely hope that Fred Thompson will choose to seek the Republican nomination for President of the United States."

That's gotta smart a little over at Romney HQ, which trumpeted Blackburn's support back in January: "With extensive experience in the public and private sectors, Congresswoman Blackburn will provide valuable insight as I move forward," Romney said in a statement at the time. "As a rising star among conservative leaders, I am proud that she has joined my exploratory committee as a senior adviser."

Thompson's entry into the race is sure to shake up the GOP field. Romney better hope Blackburn's defection is an aberration.