"I am very excited to share with you guys that William and I got engaged over the weekend," Lauren gushes on her site. "I am beyond thrilled!"
Lauren and law student William have lived together in Westwood since September and have been dating since May 2012. William, 33, used to play guitar in the pop-punk band Something Corporate and released a solo album in 2007.
"Everyone is so happy for her," a friend of Lauren's tells People. "He's such a great guy. They are perfect for each other!"