High end steak house in Lowell, Ma area?

I want to take a very special someone out for a very nice celebratory dinner. Something we would have to dress up for. I am looking for something along the lines of a steakhouse, but high end (and definitely not the outback). I am new to the area so I don't know a lot of places. Can anyone help me with suggestions? Anything in Andover, Billerica, Chelmsford, Nashua etc. would be great. Thank you.