One of the first AdSense advertisements in a YouTube video has been spotted in the wild.

The video in which the ads are embedded includes two tell-tale yellow segments in the time seek bar.

When those segments are reached during playback, a banner overlay fades on to the foot of the video including advertising slogans and inviting the viewer to click.

The banner can be hidden during the remaining playback and re-displayed to view it again.

When clicked upon, a secondary video window opens over the top of the initial clip, displaying the animated advertisment.

Spotted by a blogger called Mark, the ad is believed to be a manifestation of Google’s previously announced AdSense For YouTube programme.

But it is believed to only be accessible in certain regions around the world.