"We're excited and incredibly happy about our engagement and we look forward to a wonderful future together," the couple confirmed.
"They're so happy, doing great," a source adds. "Thrilled about it."
According to another source, Lachey proposed with a platinum, asscher cut diamond with trapezoids on the side from Bader & Garrin.
The two began dating in 2006, following his highly-publicized divorce from Jessica Simpson.
Though they briefly split last summer, they got back together a short time later.
The True Beauty host recently told Parade their relationship has lasted all this time because they openly communicate.
"You have to talk through everything," she said. "We talk daily about things that upset us. It's about having a sounding board because if you hold in all your thoughts, dreams, anger and anxiety than you're only hurting yourself."
She said they have no plans to do a reality show a la MTV's Newlyweds: Nick and Jessica, which caused strain in Lachey's relationship with Simpson, 30.
Chatting on Good Day Philadelphia last year, the Sing-Off host -- whose show was just renewed for a second season -- said he was "happy" with Minnillo, whom he described as "a very smart girl. She's far smarter than I!"
Lachey and Minnillo have another reason to celebrate: They both have birthdays Nov. 9.
Lachey will be 37; Minnillo, 30.
From: US Weekly
