"There was interest last summer, but it didn't quite happen for whatever reason. I'm just glad to find myself here now," he told the official Villa website after completing the move late on Thursday night.
"I think this is a great opportunity for me to try and win something. I think at the minute Villa are a notch above Boro and there's a great opportunity for me to play European football as well.
"The chance of European football was definitely an important factor in my decision. You always want to test yourself at the highest level.
"I had a brief stint playing European football at Spurs, but that was almost ten years ago and it will be great to get another chance this season.
"It's definitely a case that Villa's ambitions match my own. I've worked hard over the last ten years to perhaps get this chance to show what I can do on a little bit of a higher stage."