The Monty Python troupe member also has a 35-year-old daughter, Sally, and 32-year-old son, Bill, from his 30-year marriage to his wife Alison from whom he is now estranged, the BBC said.
Baby Siri is the first child Jones has had with Anna Soderstrom, his 26-year-old Swedish girlfriend of five years, the British broadcaster noted.
"I don't think people who have children are acting selfishly or unselfishly," he told The Radio Times.
"Having a child who'll be loved, to parents who love each other, is the important thing," he said. "I've a reasonable chance of living another 20 years, and hope I do, so Siri will be in her 20s."
Asked how it feels to be a new dad again at his age, Jones said he has "yet to discover how I like having another child."