The singer-turned-presenter- who proposed to TV beauty Vanessa Minnillo last November after dating for four years - threw a special cocktail reception at the London Hotel in West Hollywood, California to celebrate the couple's forthcoming nuptials but admitted he might have overdone it.
Nick - who was previously married to pop star Jessica Simpson - tweeted: "My liver is furious with me!! Great time last night at our wedding shower. (sic)"
Entertainment at the bash was provided by The Backbeats, an a cappella group who performed on season two of 'The Sing Off' which Nick presents while Nick may not have been the only one to be struggling to recover after the party with a source revealing guests including Nick's brother Drew Lachey "danced into the late hours".
A source told People.com: "Nick and Vanessa greeted guests hand-in-hand. Vanessa looked gorgeous in a white dress with a black sash. She and Nick both seemed very excited to celebrate with their families and friends.
"Everyone seemed to have a great time. It was a laid-back, yet sophisticated atmosphere. Guests danced until the late hours."