West Ham have completed the signing of midfielder Tomas Soucek on loan for the remainder of the season.
The Czech Republic international joins from Slavia Prague and the Hammers have the option to make the deal permanent in the summer.
Struggling West Ham have paid 4.5 million euros (£3.8m) now, with a further 20.7m euros (£17.5m) due to sign him permanently if they stay up, the PA news agency understands.
"We are delighted to welcome Tomas to West Ham United," Moyes told the official website.
"I think that he gives us a lot of different qualities, but most importantly he fits the profile of the player we want to bring to the club.
"He is young and hungry but with an established pedigree and proven talent."
Despite being a defensive midfield player, Soucek has hit 31 goals in 111 league appearances for Slavia, where he was also the club captain.