While Marilyn Monroe had been one of the most popular public figures in the 20th century, her busy and intense life behind the scenes has also become a subject of great interest.

Lifetime has now put the spotlight on the starlet’s personal life with ‘The Secret Life of Marilyn Monroe’, a television movie event comprised of two parts with which part one has already premiered on Saturday, May 30.

Part two of the Lifetime special is yet to air this Sunday, May 31.

The TV movie has taken inspiration from the New York Times best-selling book by J. Randy Taraborrelli with the same title; it looks into the actress’ childhood and personal struggles after rising to fame.

The four-hour special will follow the actress’ transformation from a simple Norma Jeane Mortensen born in Los Angeles to becoming a high-profile star, particularly after her marriages with playwright Arthur Miller and baseball player Joe DiMaggio.

The movie, however, places greater emphasis on the strong bond between Monroe, played by Kelli Garner, and her mentally unstable mother Gladys, from whom she inherited severe depression.

All in all, the main secret that Monroe held was the impact of the unhealthy relationship she had with her mother, played by Susan Sarandon.

In the first part of the TV movie special, one of the most striking moments was the recreation of the famous red velvet shoot by Tom Kelley. Such images have become a part of Hollywood over the years and Lifetime’s take on it has been deemed as brilliant.

"Because in the movies you’ll be famous and if you’re famous, everyone loves you,” Monroe said.

As the first part of the TV special came to an end, Gladys was shown slapping her daughter before being taken away to be sedated. Afterwards, Monroe faced the public with a lighthearted aura and told an interviewer: “With the right shoes, a girl can conquer the world!”

Aside from Garner and Sarandon, other cast members include Jeffrey Dean Morgan as Joe DiMaggio, Emily Watson as Grace McKee, and Stephen Bogaert as Arthur Miller.

Garner has become most famous for her role as Kate Cameron in the ABC period drama series ‘Pan Am.’

The trailer for ‘The Secret Life of Marilyn Monroe’ is available below. Part two airs this Sunday at 9 p.m. ET.