The Ukrainian Prime Minister released a statement last week announcing that Penn had arrived in Kyiv to film a documentary.
"American actor and film director, Oscar winner Sean Penn arrived in Ukraine," a translated statement on the Ukrainian President's official Facebook page stated.
"The director came to Kyiv specifically to record all the events taking place in Ukraine as a documentary filmmaker and to tell the world the truth about Russia's invasion of our country."
"Today, Sean Penn is among those who support Ukraine in Ukraine," the statement added.
Penn first journeyed to Ukraine in November last year to prepare for the documentary. At the time he was photographed visiting the Azov region and talking with the Ukrainian military.
During his latest visit, Penn was seen meeting with Ukrainian presidential adviser Alexander Rodnyansky. The 44-year-old Ukrainian posted a photo of the two of them to his own Twitter account, recalling his "captivating conversation" with Penn.
"On a slightly more positive note today in spite of the political and military situation: Exciting, fun and captivating conversation over dinner with @SeanPenn, who came to #Kyiv at this critical moment. #StandWithUkraine," Rodnyansky tweeted.