The 22-year old midfielder has left his role as Crewe captain to sign a four-year deal with the West Midlands club for an undisclosed fee.
Westwood, who has compared himself to Manchester United’s Michael Carrick, is excited to begin with Villa after making the move from League One to the Premier League.
"I see myself as a Michael Carrick-type of player, someone who stays out of the limelight and keeps it simple, retaining the ball and laying it off to team-mates,” he said.
"From the conversations I've had with the new manager (Paul Lambert ) I think that will fit in perfectly here.
"He said to me that he's looking for younger lads to work with him, step up and lift this club to the next level and I'm really looking forward to the challenge.
"This is a fantastic football club, a massive club and I can't wait to get started really. It's a bit surreal right now but I'll get out training with the lads tomorrow morning and take it in my stride."