Hull made their second signing on the final day of the transfer window by bringing in West Ham's Mohamed Diame.
The Tigers, who had already broken their transfer record to buy Palermo's Uruguay international striker Abel Hernandez, recruited the former Wigan midfielder for a reported fee of 3.5 million pounds.
Diame signed a three-year contract at the KC Stadium and became manager Steve Bruce's eighth new addition this summer.
Bruce told Hull's website: "His experience, both at international level and in the Premier League will be invaluable for us as we look to cement our place in the top-flight."
Besides Hernandez, Bruce has brought in centre-backs Michael Dawson and Harry Maguire, left-back Andrew Robertson, midfielder Jake Livermore and wingers Robert Snodgrass and Thomas Ince.
Hull have spent more than 30 million pounds this summer, although some of their spending was financed by the club record sale of Shane Long to Southampton for 12 million pounds. George Boyd was also sold to Burnley on Monday.
Diame scored seven goals in 79 appearances for West Ham since joining them from Wigan two years ago and featured in all four of their first-team fixtures this season.
However, he was being kept out of the starting 11 by the June signing of Cheikhou Kouyate. Manager Sam Allardyce had also recruited another central midfielder, Diego Poyet, from Charlton.