Lachey (left) and Simpson
Francis Specker/Landov; Kevin Mazur/Wireimage
It officially brings their divorce to a complete close; they were legally free to marry others in June.
Details of the settlement were not disclosed.
Simpson, 26, and Lachey, 33, were married in 2002 and starred together in the MTV reality series Newlyweds: Nick and Jessica. They split in November 2005; Simpson filed for divorce that December.
Simpson, who decamped to her own Beverly Hills mansion, has kept busy with music and movie work. She has spent the past few months shooting her latest film, Blonde Ambition, in Shreveport, La.
Lachey, who is scheduled to host a party at Pure Nightclub in Las Vegas on Saturday night, spent his time since the split renovating a Bel Air bachelor pad and amping up his music career with the gold-selling album What's Left of Me and a nationwide tour.
He's also found love again with MTV's TRL host Vanessa Minnillo, 26, whom he's been dating for eight months.
"The first few months were hard," a pal of Lachey's told PEOPLE in November. "But Nick finally realized he was in a better place."
