Scarlett Johansson and Colin Jost share unique name of their baby boy

Scarlett Johansson and Colin Jost have announced the birth of their baby boy, Cosmo.

The couple had kept their pregnancy private until earlier this week when comedian and Saturday Night Live star Jost revealed they were to become parents at a stand-up show.

He then confirmed the news on social media, writing: "Ok ok we had a baby. His name is Cosmo. We love him very much."

Jost also appealed for “privacy” and jokingly told fans to direct inquiries to the couple’s “publicist”, tagging SNL co-star Michael Che.