Left-back Shorey, 27, joins former Royals team-mate Steve Sidwell and goalkeepers Brad Friedel and Brad Guzan at Villa Park.

Shorey headed to the Midlands earlier on Thursday after Villa agreed a fee with the Royals.

And after agreeing personal terms, the twice-capped England player has signed for O'Neill's troops.

Shorey had been expected to leave Reading since their relegation last season with a number of clubs reportedly interested in his services.

The Londoner will fill the void left by Wilfred Bouma, who dislocated his ankle recently, and provide long-term competition for places.

O'Neill has made no secret of his desire to bolster the Villa squad and add strength in depth.

The former Celtic boss told Villa's website: "Strengthening the squad has obviously been in our minds for quite some considerable time.

"We have agreed a fee with Reading for Nicky Shorey - a quality natural left-back who played for England 18 months ago.

"Obviously the injury to Freddie (Bouma) has left a gaping hole on the left. Freddie had a wonderful season for us last year and this wasn't necessarily a priority for us before the injury.

"But Nicky Shorey is more than a back-up. He's a quality player on the ball and is up for the challenge."

Reading declined to disclose the fee paid by Villa for Shorey.

Royals boss Steve Coppell said: "In many ways I am very sorry to see Nicky go, but he had made his intentions clear for almost a year. We wish him well at Villa."

Shorey revealed the ambition shown by O'Neill and advice from old friend Sidwell convinced him to move to the club.

"I'm delighted to be here," he said. "It's all come out of the blue a bit but it's a great challenge for me. This is a massive club and I'm really looking forward to it.

"There were other clubs interested but this is such a big club. Obviously I talked to the manager and he's very positive and very ambitious. That's what I am - especially after last season. I want to get back into the Premier League and show people what I can do.

"So I'm just grateful for the opportunity to play for such a big club as Aston Villa. I think I can achieve everything I want in the game at a club like this.

"Villa are definitely going places. You can tell by the signings they're making and the people already at the club.

"The manager is talking very positively here and obviously the chairman's backing him up. So I want to be a part of that."

He added: "When you talk to the manager you want to get a good feel for what he's trying to do and I did straightaway with Martin. He made me feel at ease and made me feel wanted. That was a big factor.

"I'm looking forward to just getting out on the training pitch with the lads first and obviously I know Steve Sidwell very well so that's a bonus - to have such a good friend at the club who can help me settle in.

"I've spoken to Steve and he's only had positive things to say about Villa. So it's going to be great to link up with him again because we're really good mates."