The actress gave birth to their daughter last night, with proud dad Dax taking to Twitter to announce the news - and uncover their unusual baby name choice of Lincoln Bell Shepard.
Bucking last year's baby name trend in the US for names influenced by pop culture, celebrities and even the Olympics, the proud new parents have certainly chosen a unique name for their first child.
While the name has Presidential connotations and refers to a city in the UK, 'Lincoln' as a baby name has been rising in popularity over the years.
According to Babynamesworld, 'Lincoln' first rose to prominence as a boys name and was the 300th most popular moniker for boys in 2006.
However in recent years it's become a girls name, popping up on lists for 'cool names for your baby girl' over in the US.
Kristen and Dax's baby name choice mirrors Jessica Simpson and Eric Johnson's decision too, as they also opted for boys name with daughter Maxwell Drew.
Interestingly, both couples gave their daughters more traditional girls monikers for a middle name - a move many baby name books advise if plumping for a 'boys name' as a first name.
Either way, Kristen and Dax have definitely chosen an original celebrity baby name for their new baby bundle.
Huge congrats to the new parents and tell us what you think of their name choice over on Twitter now.