And, of course, fans are interested in the Irishman himself, Frank Sheeranespecially since there's been some controversy about whether or not Sheeran's confessions in the 2004 book I Heard You Paint Houses: Frank "The Irishman" Sheeran and Closing the Case on Jimmy Hoffa are factual. Here's what we know about Sheeran.

Who was Frank Sheeran?

Francis "Frank" Sheeran was born in 1920 and grew up in an Irish community in Darby, Pennsylvaniaa small town outside of Philadelphia. Sheeran joined the Army when he was 21, and he saw 411 days of combat throughout Europe during World War II, including the invasions of Sicily and Germany.

According to the I Heard You Paint Houses book, which was written by Sheeran's attorney Charles Brandt, the Irishman says that he participated in war crimes like revenge killing and mass executions during his time in the Army. After his discharge from the military in 1945, Sheeran returned to Philadelphia and began working as a truck driver, where he later met crime boss Russell Bufalino in 1955.

Sheeran reportedly began doing odd jobs and favors for Bufalino, which later morphed into his becoming a hitman for the mob. Eventually, Sheeran said that he was the man responsible for the infamous murder of "Crazy" Joe Gallo , which is a claim still being disputed to this day.

Did Frank Sheeran really kill Jimmy Hoffa?

Former Teamsters Union President Jimmy Hoffa disappeared from the Machus Red Fox restaurant in Bloomfield Township, a suburb of Detroit, on July 30, 1975. He was declared legally dead in 1982, and attempts to find out who killed him and/or what happened to his body have been futile.

Hoffa met Sheeran through Bufalino in 1957, and they became close professionally and personally, with the Irishman reportedly intimidating and killing Hoffa's union rivals for himSheeran estimates the number of people he killed to be about " 25 to 30 ." Hoffa later made Sheeran the union boss of one of the local Teamster chapters in Delaware.

Sheeran claims that he was ordered to killed Hoffa after the union leader's relationship with some mob leaders soured. In I Paint Houses, Sheeran explains that he lured Hoffa to a house in Detroit, then shot him twice. Hoffa's body was then disposed of in a crematorium . Some reports state that Sheeran said he tried to stop the hit on Hoffa, while others say that he " felt nothing " when ordered to kill his friend.

Sheeran's confessions in his book are widely disputed, as there's no evidence that ties him to the murder. A man that knew Sheeran says that he never even " killed a fly ," and the blood splatter found in the Detroit house where Sheeran claims to have murdered Hoffa doesn't match the union bosss DNA. But while some say that Sheeran was only a low-level criminal, another report states that Sheeran was one of only two non-Italians named on former NYC mayor Rudy Giulianis list of top mob members in 1985.

How did Frank Sheeran die?

Sheeran died of cancer on December 14, 2003 at the age of 83. According to his obituary, he was buried at Holy Cross Cemetery in Yeadon, Pennsylvania.

Prior to his death, in 1981, Sheeran was found guilty for 11 charges of labor racketeering, and he was sentenced to 32 years in prison. He ended up serving 13 years of his sentence.

Who plays Frank Sheeran in The Irishman?

Robert De Niro took on the role of Sheeran in The Irishman, a role that he's been attached to ever since he first brought the book to Scorsese in 2007 .

"He [De Niro] sat down, he started talking about the book, but he became...I could see he was really emotionally involved with the character," Scorsese told Esquire UK . "So much that he couldn't describehe couldn't really speak."

De Niro later told the publication that he was so moved by the book because he "believed everything that he [Sheeran] said in the book: I can tell by the dialogue, I can tell by the situations the whole milieu, the whole feel was real."

And while some parts of The Irishman have been criticized for being fictionalized , some parts are very real. Two FBI agents really did visit the nursing home that Sheeran was living in to try and get him to confess to Hoffa's murder, but he refused, and this scene is depicted towards the end of The Irishman.

Is Frank Sheeran related to Ed Sheeran?

While rumors that the two Sheerans were related started when Irishman actor Stephen Graham reportedly told The Sun that Ed had told him that Frank was "his distant uncle," a team of genealogists told The Daily Mail that "birth, marriage and death records in Britain and America dating back to 1845 show no direct link between the two men."