The singer-actress was said to be “flipping out” about Lachey’s engagement to actress Vanessa Minnillo.
But in an interview with Ryan Seacrest on his KIIS-FM radio show earlier today, the 30-year-old Dukes Of Hazzard star said: 'I am extremely, extremely happy for him, I don't know where all those rumours came from.
'My mother actually called me and said that everyone was saying that I was 'saddened'. I was just in complete shock – I couldn't be more happy for Nick.'
She added: 'Our relationship was over a really long time ago, and it would be nice if everyone could move on with us and really just celebrate the love between him and Vanessa.
'I do, and I really wish them nothing but the best.'
Simpson told Seacrest that she is more than happy with her current boyfriend Eric Johnson and plans to spend Thanksgiving with him in New York City.
She said: 'My first New York Thanksgiving! I know his family's going to be with us on the float at the Macy's Day Parade, and my family will be there.'