McCullum was one of the biggest stars of the World Cup in New Zealand and Australia, with his explosive batting tearing several teams apart.
He will play for the Birmingham Bears, the defending champions, in the T20 Blast competition this summer, which promises to be a memorable one for England???s second city.
Edgbaston will host one of the Ashes Tests, and Warwickshire – second in the Championship, and runners-up in the Royal London club last season – are once again expected to challenge on all fronts.
Povey told Sky Sports News: ???This year???s a particularly exciting one for Edgbaston. We???ve got an Ashes Test coming to the ground for the first time in a number of years. We???ve got the T20 title to try to defend. Improving is one of the challenges for our new captain, Varun Chopra, and coach Dougie Brown.
???Expectations are higher. The more success we have, the more people expect you to succeed. The focus has very much been on improving individuals as players and improving as a team.???
The sight of McCullum smacking bowlers around the park is likely to be a real highlight of the season.
???It???s a bit of a change for us ??? we???ve been reluctant to sign a second overseas T20 player,??? Povey said. ?????We did that last year with some success. But Brendon is clearly a massive name in world cricket, an incredibly explosive batsman.
???He comes with strong references from (Warwickshire off-spinner and Kiwi overseas star) Jeetan Patel and he???s well known to some of our senior guys. We are really excited to see a truly world class player coming to Edgbaston.???
Coach Dougie Brown says expectation management will be one of his biggest challenges this season, and McCullum???s signing will not make his job any easier.
???Last year has gone now. We???ve got to focus on what we are looking to try and achieve this season,??? he said. ???To be down the stretch, competing in all three competitions at the back end of last season was excellent.
???We???ve got to manage expectations of ourselves this year. Signing Brendon is obviously very positive for all of us ??? let???s hope he scores some runs!
???There???s a lot of world-class players coming to England this year. I don???t know why, all of a sudden this year and not in previous seasons. But it???s really exciting to have all these top players coming, and not disappearing to other parts of the world to play.?????