Lachey, who is said to be overjoyed following the birth of his son, was romantically linked to Cavallari after his divorce from singer Jessica Simpson in 2006.
A year after their wedding, the celebrity couple appeared in their own reality series "Newlyweds: Nick & Jessica" (MTV, 2003-05).
The show became an unexpected hit and spawned a number of spin-off variety specials for the high-profile pair, such as "Nick & Jessica's Family Christmas" (ABC, 2004).
Within a few short years, however, the band went on hiatus after being eclipsed by fellow teen idols the Backstreet Boys and 'N Sync.
It was at that time that Lachey's career took an unexpected, but highly profitable turn with his marriage to fellow pop star, Jessica Simpson.
As their popularity grew - especially Simpson and her dimwitted persona - the rumor mill also went into high gear, speculating on the shaky state of their union.
Despite their earlier claims to the contrary, the predictions proved true when the couple separated in the fall of 2005.
He just recently broke up with Kristin Cavallari of "Laguna Beach" and is currently dating Vanessa Minnillo, the MTV and Entertainment Tonight reporter.
Here's the story: Nick's Slip of the Tongue March 29, 2006 It looks like Nick Lachey has had a lightning fast rebound from his reported breakup with "Laguna Beach" teen Kristin Cavallari.
Soon enough, pals Eva Longoria, Christina Applegate and Christina Milian all joined the pop star for a rollerskating themed shoot.