A silly picture of a grinning President Barack Obama with a student from the University of Colorado has gone viral after being posted on the internet.

The rare unofficial snap of Obama, which shows him with his arms round the shoulders of Madalyn Starkey, quickly became a trending topic after she uploaded it to her Twitter account.

In the photo, Starkey poses beside the most powerful man in the world with her eyes wide open in mock shock and her fingers pointing at him in disbelief.

The picture was taken at a local bar called Sink when Obama stopped off while travelling through Colorado on his way to deliver a speech.

Starkey said she had no idea the photo would create such a stir after she uploaded it on to her Twitter account.

She told Yahoo News: "That's my face in about 95 percent of my pictures."

However, she has been making the most of the attention on her Twitter feed by tweeting: "Woooo, never knew a tweet could blow up like that. Neat!"

She also joked with another Twitter user: "Bet you wish you had taken me to prom now, huh?"

Move over the Ridiculously Photogenic Guy, there's a new boss in town.

IBTimes UK has a look at some of Obama's funniest photos to date...