In 2004 the CIA used the popular TV actress and star of CIA drama Alias Jennifer Garner in a recruitment video to be shown at colleges and similar venues. The video was made available for a time on their website though is sadly no longer accessible.
Garner was not paid for her time but apparently appeared in the recruitment ad voluntarily, out of a sense of patriotism. Indeed, the casting of an actress known for playing a CIA agent in a CIA recruitment ad did both parties a lot of favours, as it became a story in itself, propelling both Garner and the her heartily pro-CIA message onto Good Morning America and elsewhere.
The Agency were terribly pleased, as recorded in their internal publication What’s News at CIA?. You can download the edition mentioning Garner here (PDF, 67KB).