This is Dominique Harrison Bentzen, 22, a student at the University of Central Lancashire.
According to the Mirror, she didn't take the money but, "was so touched by the man's kind gesture that she set herself a mission to help him."
She told the Mirror:
He has been homeless for seven months through no fault of his own and he can't get work due to having no address.
It took me four nights of driving round Preston to find him and I was beginning to lose hope that I would see him again, to thank him personally for his kindness.
Luckily I had my mum and her car to help me.
Dominique found the man four days later, and set up a Facebook group and a charity fundraising page for him.
And now over £20,000 has been raised!
@Help_Robbie #prestonhomelesshero #helprobbie Amazing guys you have smashed 20K👏👏👏👍
Dominique told the Mirror she's doing it because she couldn't simply "just give him the money". She said: "I have to go through the right channels so I will be spending 24 hours through the day and night as a homeless person to understand the difficulties they face each day."
She added: "If people can sponsor me £3 - as Robbie attempted to give me his only £3 - in the hope of collecting enough to get Robbie a flat deposit so that he can be safe and warm."