Cape Town - South Africa leg-spinner Imran Tahir has signed for Derbyshire for the bulk of the 2017 season, depending on his international commitments.
Tahir, who is 37 but is ranked the world's number one T20 bowler, will be available from late June in all formats, assuming he is not picked for the Proteas in that time.
Tahir joins Derbyshire after playing for Nottinghamshire last season, and he has also played for Hampshire and Warwickshire in the past.
Chairman Chris Grant said: "At the end of the season, we committed to investing in top quality players to improve the squad and ensure we could compete more strongly in 2017.
"This signing clearly demonstrates that we are delivering on that commitment and we look forward to welcoming Imran to Derbyshire."
Director of Cricket Kim Barnett added: "We are keen to strengthen our squad with experienced match winners who will also help our talented youngsters.
"With his vast international and domestic experience here in England, Imran fits the bill perfectly.
"He is one of the best leg spinners in the world and we're very excited to have him on board. Not only will Imran bring an added dimension to our bowling line up, his influence on the team and players, such as Matt Critchley, will be immense.
"Whilst our initial plans are very much focused on next summer, we are both going into this with an open-mind and a view to looking at long term options."
Imran said: "I love playing cricket in England and I'm looking forward to playing a senior role at Derbyshire.
"I've learned a lot over the years and if I can pass my knowledge on to youngsters and help win matches, then it’s a great option for me."