Nick Lachey detailed his run-in with his ex-wife, Jessica Simpson, on an airplane.

Nick sat down with host Andy Cohen on Wednesday’s episode of “Watch What Happens Live” … and went into detail about bumping into Jessica on a flight from Los Angeles to Hawaii. Nick confirmed to Andy the random encounter with his pop star ex-wife was “strangely okay.”

Check out the clip … Nick casually explains to Andy that he and his family spent 6 and a half hours on the flight in the “vicinity” of Jessica and her family. Nick noted that “everyone was very, very cordial, very respectful.” 

We broke the story … Nick and Jessica had an awkward encounter on a flight to Hawaii in April, where they both were sitting in first class. Jessica even switched seats to keep her distance, while both of their current partners were also on board.

As you may know, Nick tied the knot with Jessica in 2002, but divorced 4 years later. They have no kids together.

Jessica then got hitched to NFL player Eric Johnson in 2014, but they split last year, and now Jessica is datingThomas Eisenhood, a roadie in the music biz.