Hollywood star Leonardo DiCaprio has been challenged to a public debate in London, on the subject of corruption in Malaysia.

The challenge was issued by environmental NGO Bruno Manser Fund (BMF) in a letter to DiCaprio dated Oct 4, which was gently worded as an "invite" to the Oct 14 event.

"We would like to invite you to debate the detrimental effects of grand corruption on Malaysian society and the environment.

"In particular we would be interested in learning more on the financial ties of the Leonardo DiCaprio Foundation, Appian Way Productions and you personally with Riza Aziz, Low Taek Jho and their associates," the letter read.

Appian Way Productions is a company set up by DiCaprio.

Riza is the stepson of Prime Minister Najib Abdul Razak, while Low, better known as Jho Low, is a tycoon with close links to Riza.

Both were implicated in US Department of Justice lawsuits which claimed that more than US$3.5 billion was misappropriated from 1MDB.

DiCaprio was also referenced in the suits as Hollywood Actor 1, and it is alleged that 1MDB money was used to finance his gambling with Riza and Low.

There are also allegations that 1MDB-linked money had been donated to DiCaprio Foundation.

The debate is being held in conjunction with the European launch of the documentary 'Before the Flood', which DiCaprio stars and helped produce.

"DiCaprio needs to understand that we can’t save the environment if we fail to stop corruption," said BMF executive director Lukas Straumann in a media statement.