Hull sign Altidore and Olofinjana
"Altidore arrives at the KC stadium on a season-long loan deal from Spanish side Villarreal subject to a work permit being granted," Hull said on their website.
"The Tigers have the option of making it a permanent deal at the end of the campaign."
The 19-year-old striker was unveiled along with Olofinjana who agreed a four-year deal, the club said. Stoke said Olofinjana was sold for three million pounds.
Altidore scored the opening goal when United States shocked Spain 2-0 in the Confederations Cup semi-final in South Africa in June.