One well-meaning one, as Illawarra charity Darcy House discovered when it was chosen for WIN's new TV series, The Secret Millionaire.

The show brought Danny Wallis, millionaire and CEO of a Melbourne IT company, to volunteer undercover at three Wollongong charities.

After his experience, Mr Wallis gave thousands of dollars of his own money to the charities.

At Darcy House, a drop-in centre for disadvantaged people in the Illawarra, senior support worker Megan Smith said she assigned difficult tasks to Mr Wallis.

"He prepared meals, scrubbed the shower floor and picked up rubbish," Ms Smith said.

"He talked to the clients to get a feel of what Darcy House does for them."

Mr Wallis said his time at Darcy House taught him homeless people were exactly like him, but had suffered setbacks in life.

"It's quite scary to think it could happen to any of us," he said.

"They aren't freaks, they're real people with real emotions who've found themselves in a position they can't control."

Ms Smith said she had no idea Mr Wallis was an undercover millionaire, but it took some convincing to make him scrub the bathroom floor.

"He wasn't happy about it," she said.

"We were told to make him do lots of chores so we did."

During filming, area charities were only told they were in a documentary to raise awareness for services in the Illawarra.

Ms Smith said her first impression of Mr Wallis was that he was out of his comfort zone.

"He didn't seem to have a lot of idea about homelessness," she said.

"I think he took a lot from it and ... realised there are a lot of people that aren't as fortunate as himself."

Mr Wallis was positive about the skills he learned at Darcy House and the show in general.

"I'll have more awareness of people in general now and be more active in society," he said.

"The show reveals the hardships people go through that some of us take for granted."

After three days volunteering in modest attire, Mr Wallis returned to Darcy House wearing a suit, with a $20,000 cheque.

Ms Smith found it hard to believe she had been on the show.

"We had to do the end take again because I wouldn't believe it was real."

The Wollongong-based episode of Secret Millionaire airs tonight at 9.30.