A Chicago police officer and his partner are warming hearts across the nation, with an video of them giving a coat to a homeless man quickly becoming an internet sensation.

The story dates back about three weeks ago, when officers Peter White and Bob Osborne of the 015 district on Chicago's West Side saw a vagrant walking in traffic on an off-ramp of the Eisenhower Expressway.

Fearing the man would hurt himself or cause and accident, the patrolmen pulled over and gave the man a citation.

But they also noticed he was wearing a thin threadbare coat wholly inadequate for Chicago's brutal winter weather.

Officer White gave the man an old winter coat of his own, and even helped him zip up

'I asked him, if he was going to stay out there why didn't he have a jacket for the winter?' recalled White.

The man replied that he'd tried to get a coat from a charity coat drive, but had arrived too late to get a warm coat.

The two cops promised to bring the man a winter coat the next time they saw him.

Officer White (right) gave away the coat, but didn't realize his partner Osborne (left) was secretly filming the act of kindness

'You could see he didn't really have any family left, or they didn't let him back in anymore,' said Osborne.

Officer White retrieved one of his own old coats from home that night, and kept it in their patrol car to give the man.

But three weeks passed until finally they spotted him again.

As the cops pulled over, the man, fearing another citation, protested that he hadn't been disrupting traffic this time.

'I know, I know,' said White, as he hopped out of the cruiser. 'I brought you that coat I promised.'

What White didn't know was that his partner Osborne was secretly filming the exchange from the car's passenger seat.

Chicago cops White (right) and Osborne (left) spoke the the press on Wednesday

'I just thought our friends would see something positive about the police department, because there's so much negative,' Osborne explained.

Little did Osborne suspect that the video he posted on Facebook Monday, intended mainly for friends, would become a popular sensation.

The partners are hoping to turn the attention toward a good cause, starting a coat donation drive at their district station in Chicago's Austin neighborhood.

The Chicago Police Department has been the subject of controversy in recent years, with the 2014 shooting death of Laquan McDonald leading to the ouster of one police commissioner.

In January, Illinois Attorney General Lisa Madigan requested the U.S. Justice Department conduct a civil rights investigation of the department.

Officers White and Osborne don't feel like their gesture of kindness sets them apart from other police though.

'It felt like an everyday thing for us,' said White.