The 33-year-old Norwegian was at Villa Park on Wednesday night to see Graham Taylor's side beat Manchester City after spending the afternoon discussing terms.

A report on Villa's website said Johnsen had passed a medical on Thursday.

Johnsen, who has been plagued by injury over the past three years, was released by United on a free transfer at the end of last season.

"I'm feeling fitter than ever and I want to put the injury nightmares behind me," Johnsen told Villa's website.

"I feel fine. I had a problem called `Jumper's Knee' which I had problems with. But that's fine now. I've come through the medical and I'm just looking forward to getting started.

"Villa were mentioned quite early in the summer and when the name came up again, I was quite happy to discuss the move.

"There was interest from other clubs, but this was my first choice.

"I'm 33 now, but I can play on at the top level. It's up to you how long you want to work and stay fit and I want to play."

Taylor said: "I've got in Ronny an excellent player."

The move comes as Villa boss Graham Taylor warned Ozalan Alpay that he will be frozen out if he fails to move before Saturday's transfer deadline.

Taylor wants a united dressing room and that means no place for anyone wanting to leave such as the transfer-seeking Turkish World Cup star.

Speaking after Villa's 1-0 win over Manchester City, the former England boss said: "There hasn't been a club in for him yet. There might be - we'll have to see.

"If not, we'll probably go through to the next transfer window, and I can't have players who are demanding transfers in the dressing room."