Kim Kardashian West and Kanye West have named their fourth child Psalm West. 

The couple shared the big baby naming news Friday afternoon on Kim's Instagram page. 

She revealed their baby's name along with a screenshot of a text and photo Kanye sent her about the arrival of their fourth child. 

Psalm West joins North, Saint and Chicago. Chicago, who's a year and a half, was also born via a gestational carrier. North, the oldest, is five. The new baby is the couple's second son after Saint. 

Kardashian West had tweeted last week that their new arrival is "Chicago's twin lol I'm sure he will change a lot but now he looks just like her."

The birth comes after she disclosed she's studying to be a lawyer through California rules that allow for professional mentorship over law school.

The Associated Press contributed to this report.