Trending: Why Jim Wolf's makeover video went viral

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Media captionThe two-hour make-over of a US Army veteran is shown in two minutes

A time-lapse makeover of a homeless US man has been watched more than 13 million times on YouTube in the past week.

In two minutes, former soldier Jim Wolf is shown making the transition from bearded and bedraggled to well-groomed and sharply-suited. Since then, the 54-year-old - who has long struggled against poverty, homelessness and alcoholism - has reportedly started to attend Alcoholics Anonymous meetings and is now staying with his sister.

Producer Rob Bliss made the video to raise awareness and funds for a Grand Rapids homeless charity, Degage Ministries - which has received $50,000 (£30,000) in donations as a result.

Mr Wolf's is not the first story of this kind to gain such traction in social media networks. In September, donations of more than $110,000 (£70,000) poured in for Glen James, a homeless man in Boston who returned a lost bag containing £26,000 in cash and travellers cheques. Billy Ray Harris was able to buy himself a house in Kansas with £110,000 given by strangers touched by his honesty after he returned a £2,500 diamond ring accidentally dropped into his change cup earlier this year.

And in 2011, offers of radio work flooded in for Ted Williams after his smooth baritone was recorded by a local newspaper reporter who saw him asking for money by an Ohio roadside.

The release of the Jim Wolf video - timed to coincide with Veterans Day - has focused minds on the issue of homelessness. Even so, Mr Bliss, who makes viral videos for a living, described the response as "pretty incredible" - far outperforming any other content he has produced.

"The number one thing that makes a video likely to go viral is the feeling it creates," he told the BBC. "The stronger that feeling, the more successful it will be."

Alastair Murray, Project Director at Housing Justice, a UK-based Christian campaigning charity says the video reminds the audience of the possibility of losing a job, a home, and a stable life. "This video helps people see the real person behind that bearded needy person about whom they feel awkwardness - there's a transformation into a person with whom you'd be happy to have a chat," he says.

Reporting by Michael Hirst