Donald Trump is being accused of crashing a charity event for children that he did not donate any money to, and the billionaire has only given $7.8 million from his own pockets to charities since the 1980s, a new report claims.

A months-long investigation by the Washington Post found that Trump sought credit for numerous charities that he did not donate to or instead claimed other people's donations as his own.

In an interview earlier this year, Trump said: 'I give mostly to a lot of different groups.'

When asked if he could name the groups, he responded: 'No, I don't want to. No, I don't want to. I'd like to keep it private.'

It's unclear exactly how much the Republican presidential candidate for president has donated in total, since he declined to release his tax returns.

But since the early 1980s, the Post found that Trump had donated $7.8 million in charitable giving.

Billionaire Donald Trump (center) has only given $7.8 million from his own pockets to charities since the 1980s as he often boasts about the large amounts of money he has donated, a new report claims

Through the years, Trump has vowed to give away the proceeds of Trump University and his salary earned from 'The Apprentice'. It's unclear if he followed through with any of those promises. He is pictured above presenting a check during a campaign event in 2016

Through the years, Trump has vowed to give away the proceeds of Trump University and his salary earned from 'The Apprentice'. He has also promised to donate to the charities picked by the contestants on 'Celebrity Apprentice' as well as donate $250,000 to a charity that would help Israeli soldiers and veterans.

However, it's unclear if he followed through with any of those promises, as it together would have totalled into the millions.

According to the Post, between 2008 and 2016, of the 420-plus charities that have some association with Trump, he has only donated one personal gift to the Police Athletic League of New York City in 2009. That donation was less than $10,000.

Over his lifetime, there is only one charity that he has given the most money to and that's his own, the Donald J. Trump Foundation, which he started in 1987.

Tax records show that the Trump Foundation received $5.5 million from Trump. He has not donated anything to his organization since 2008.

Other donations from outside people have totalled to be $9.3 million.

The Trump Foundation's largest-ever gift, $264,631, was used by the organization to renovate a fountain outside the windows of Trump's Plaza Hotel, the Post reported.

The smallest-ever gift to the Trump Foundation was $7, which was paid to the Boy Scouts in 1989.

That same time, the businessman's oldest son was 11 years old and it cost $7 to register a new Scout.

Between 2008 and 2016, of the 420-plus charities that have some association with Trump (above), he has only donated one personal gift to the Police Athletic League of New York City in 2009. That donation was less than $10,000

Trump also used money from his foundation to settle legal disputes that involved his for-profit companies. He also used the money to purchase two large portraits of himself, including one that is hanging on the wall at a Trump-owned golf resort inside the sports bar.

In providing questions to the Trump campaign about his charitable giving, they responded to the newspaper and said: '(He) has personally donated tens of millions of dollars . . . to charitable causes.'

About 70 per cent, $5.5 million, of the personal giving that was identified by the Post from Trump, went to his foundation before 2008.

Since 2008, the foundation's tax records show that Trump has not donated any money to it.

Pro-wrestling executives Vince and Linda McMahon donated $5 million to the foundation.

Back in January, Trump did not participate in a GOP primary debate while he was feuding with Fox News.

The largest donation from the Donald J. Trump Foundation - $264,631 - went to a fountain (above) outside of the Plaza Hotel which Trump previously owned

Instead, he held a televised fundraiser for veterans, where he said he'd donate some of his personal money, $1 million, to the cause.

No evidence could be found that the billionaire had even done so, as his then campaign manager Corey Lewandowski said that the money Trump gave was donated in private and would not 'share that information' as to who or what group it went to.

Not long after, Trump donated it to the Marine Corps-Law Enforcement Foundation.

Back in 1996, the Association to Benefit Children held a ribbon-cutting ceremony in Manhattan for a new nursery school that would serve children with AIDS.

TV stars Frank and Kathie Lee Gifford, who were major donors to the charity, then-Mayor Rudolph Giuliani and former mayor David Dinkins were all in attendance at the ceremony along with Donald Trump.

'Nobody knew he was coming,' Abigail Disney, another donor sitting on the dais, told the Washington Post.

'There's this kind of ruckus at the door, and I don't know what was going on, and in comes Donald Trump. [He] just gets up on the podium and sits down.'

Trump is pictured above with then New York Mayor Ed Koch who is shaking hands with then Manhattan Borough President David Dinkins at the Lasker rink in Central Park in 1988 - one year after starting the Trump foundation

The charity's executive director then and now, Gretchen Buchenholz, said that the billionaire businessman wasn't a donor at all.

Once the program started, many of the guests sitting on stage reportedly questioned why Trump was at the ceremony.

'Frank Gifford turned to me and said, 'Why is he here?' ' Buchenholz recalled.

After the program ended, Trump left and allegedly did not offer an explanation as to why he attended and did not provide a donation.

'I mean, what's wrong with you, man?' Disney recalled of Trump after the ceremony had ended.