Gregory sees Mellberg, 23, who signed from Spanish side Racing Santander, as Gareth Southgate's longterm replacement. Capped 16 times for his country, Mellberg was in Sweden's Euro 2000 squad and tied up a five-year deal after four hours of talks.
Gregory was delighted with the signing, saying: 'Not many Scandinavians have come into the Premiership and not been successful. 'What I like about him is that he has strength and surprising pace for such a big lad and that is an essential quality in our game. I believe he will be an outstanding success here.'
Mellberg may be eligible for the InterToto Cup against Croatian minnows Slaven Belupo this weekend.
Villa will try to overturn a 2-1 deficit from the first leg in the third round tie. Mellberg said: 'I've been waiting for this to happen for quite some time. I'm very pleased, I knew as soon as Villa wanted me, that I wanted them.
'It's a big club in a big league. When I spoke to the manager I knew immediately this was the club for me as his thoughts were very similar to my own.' Derby County have been rocked by the news that captain Darryl Powell has confirmed he is unlikely to sign a new deal.
The Jamaica midfielder has just 12 months left on his existing deal and said: 'Unless something is sorted out in the next few weeks, I can't see I will sign another one. 'Everyone wants to play in the top division and I am no different but if I had to drop down a division, I would.' Powell continues to rule out a move to Wolves.
