While it hasn't been officially confirmed, reports have claimed the couple decided on Michael.
According to Good to Know, Pippa and James chose the name Michael for their first born son for a number of special reasons.
A source said, 'Not only is it the name of Pippa and Kate’s father, Michael Middleton, the name also carries a lot of significance for Pippa’s husband James.'
Michael is the name of James’ older brother who disappeared in 1999 while attempting to climb Mount Everest aged just 22.
At the time of the child's birth, a spokeswoman for Pippa Middleton and her husband said, 'James and Pippa have had a baby boy. He was born Monday 15th October at 1.58pm, weighing 8lb and 9oz (3.8 kilos). Everyone is delighted and mother and baby are doing well.'
This article originally appeared in New Idea.