Russian President Vladimir Putin and US President Donald Trump
US President Donald Trump and Russia's President Vladimir Putin shake hands during a meeting on the sidelines of the G20 Summit in Hamburg, Germany, on July 7, 2017 (AFP).

With Russia threatening to invade Ukraine, comedian Bill Maher on Friday mocked former president Donald Trump's relationship with Vladimir Putin.

"Putin is known to be secretive, but when we interviewed him for this, he was an open book," Maher said on his HBO Real Time program, introducing a Putin-themed version of the segment "24 Things You Didn't Know About Me."

No. 1 on the list was, "I'm selling the pee tape as an NFT."

The list also included, "I own a small hotel chain in the United States called the Trump Organization."

Watch below.

24 Things You Don't Know About Vladimir Putin | Real Time with Bill Maher (HBO)