While the Oscar-winning actress has yet to comment on her new relationship status, the 39-year-old and Kail became engaged last December, around the same time as it was confirmed they were expecting their first child together.
‘They’re very happy and thrilled to be bringing a baby into the world,’ a source revealed to Us Weekly in January.
Michelle and Thomas met while working on the FX mini-series Fosse/Vernon, which premiered April last year.
The same month, Michelle filed for divorce from her husband of less than a year, singer-songwriter Phil Elverum. The pair had married during the summer of 2018.
Kail divorced actress Angela Christian towards the end of 2018.
Michelle also has daughter Matilda, 14, from her previous relationship with the late Heath Ledger.