From the Politico:

At 7:57 p.m. Eastern time Wednesday, while taping “The Tonight Show with Jay Leno” for broadcast later in the evening, Fred Thompson finally said: “I’m running for president of the United States.”

The studio audience responded with thunderous applause.

Thompson rejected the notion that he has waited too long to get into the race for the White House.

“People treat politicians sort of like the dentist — they don’t have anything to do with them till they have to,” he said.

Once it airs we will have the full video of Thompson’s appearance.

Update

Here is the entire video of Fred Thompson on Leno:

His strongest statement was that in which he said America has shed more blood for the freedom of others than any other nation and he’s not going to apologize for it. I think that will resonate with Republicans disenchanted with the current crop of candidates.