Talk about cutting someone completely out of your life.
Appearing on Bravo's "Watch What Happens Live" with his boy band 98 Degrees, the singer divulged the information in response to a fan question about when he last saw or spoke to Simpson.
"Is this the part where I can plead the 5th? It's been years, honestly. Yeah, years," Lachey said. "Honestly, probably six years. It was like another lifetime ago."
Lachey, 39, and Simpson, 32, married in 2002 to much fanfare, starred in an MTV reality series for three seasons that showcased their nascent marriage, then later divorced in 2005. Lachey went on in 2011 to marry Vanessa Minnillo, with whom he has a son; Simpson is currently engaged to and expecting her second child with former NFL player Eric Johnson.
But the love story was still on host Andy Cohen's mind when he asked Lachey if he ever reminisced by curling up and watching old episodes of "Newlyweds: Nick and Jessica" on DVD.
"I have not. As you can imagine, that's not popular viewing in my house. You know, we don't sit around as a family and watch the old DVDs," he said, laughing.
Lachey was later enlisted in a game of Cohen's "Plead the Fifth," in which celebs have to answer awkward personal questions or invoke the 5th Amendment. Simpson and her family were still the topic of discussion
"What is the best thing about no longer having Joe Simpson as a father-in-law?" Cohen asked.
His brother, Drew Lachey, took the bullet on that one, blurting out: "Can I answer this? Everything!"
But Lachey still came clean and told America how he really felt.
"The best thing about not having Joe Simpson anymore as a father-in-law is I don't have to play grab-ass under the table on Easter Sunday," Lachey laughed, making Cohen blush. "It may not be [funny] tomorrow, but it is tonight."
He also said that MTV's "Making the Band" spawn O-Town was the most overrated boy band of all time. Sorry O-Townies. Watch his game show moment below.
Follow Ministry of Gossip @LATcelebs.