The actor has been dating Noor Alfallah, 29, since at least April last year after they were spotted in public.
TMZ reports she is eight months pregnant with their child.
The Scarface actor is 83 years old, meaning he would be 101 when his new child reaches 18.
He already has three children to two different women.
He shares daughter Julie Marie with his ex-girlfriend, Jan Tarrant; and also has 22-year-old twins with Beverly D'Angelo.
Alfallah has been linked in the past with billionaire Nicolas Berggruen and Mick Jagger.
Pacino has previously mentioned how important his children are to him.
He told The New Yorker back in 2014: "I'm responsible to them.
"I'm a part of their life. When I'm not, it's upsetting to me and to them.
"So that's part of the gestalt. And I get a lot from it. It takes you out of yourself."
Page Six says Pacino and Alfallah have been dating since at least April last year.
However, the outlet spoke to a source who suggested they could have linked up earlier than that.
They told Page Six: "Pacino and Noor started seeing each other during the pandemic.
"She mostly dates very rich older men, she was with Mick Jagger for a while, and then she dated Nicholas Berggruen.
“She has been with Al for some time and they get on very well. The age gap doesn’t seem to be a problem, even though he is older than her father.
“She moves with the wealthy jet-set crowd, and she comes from a family with money.”
Pacino isn't the only A-lister who has decided to have a child later in life.
Robert De Niro shocked everyone when he revealed he had become a dad for a seventh time earlier this month.
The 79-year-old actor broke the news in an interview with ET Canada after correcting the interviewer on how many kids he has.
The star shares his oldest children with his ex-wife Diahnne Abbott, a son called Raphael and an adopted daughter called Drena.
De Niro also has two sons called Julian and Aaron that he shares with another ex, Toukie Smith, and son Elliot and daughter Helen with his ex-wife Grace Hightower.
An interviewer mentioned his six children, and he corrected: “Seven actually. I just had a baby.”Featured Image Credit: Associated Press / Alamy Stock Photo. Instagram/Noor Alfallah