Hollywood star Sean Penn, who is known for his association with anti-war and humanitarian causes, is in Ukraine filming a documentary on the Russian invasion, reports 'Variety'.

The Oscar winner appeared at a press briefing on Thursday (U.S. Pacific Standard Time) in Kiev, listening to government officials of Ukraine talking about the ongoing crisis.

The doc is a Vice Studios production in association with Vice World News and Endeavor Content. The actor last visited Ukraine in November 2021 to start the preparations for his documentary by visiting with the country's military installations, 'Variety' reports.

"Penn has visited the Office of the President and spoken with [Ukrainian] Deputy Prime Minister Iryna Vereshchuk, as well as local journalists and members of the Ukrainian military," 'Variety' quoted 'Newsweek' as reporting.

The Office of the President issued a statement through the Ukrainian embassy praising the Oscar-winning actor and filmmaker. The statement's translation accessed by 'Variety' read: "The director specially came to Kyiv to record all the events that are currently happening in Ukraine and to tell the world the truth about Russia's invasion of our country."

The statement added: "Sean Penn is among those who support Ukraine in Ukraine today. Our country is grateful to him for such a show of courage and honesty. Sean Penn is demonstrating bravery that many others have been lacking, in particular some Western politicians.

"The more people like that -- true friends of Ukraine, who support the fight for freedom -- the quicker we can stop this heinous invasion by Russia."