West Ham have completed the signing of former Bolton defender Joey O'Brien.

The 25-year-old Republic of Ireland international has featured as a trialist during pre-season and started today's win over Real Zaragoza at Upton Park.

O'Brien has moved on a free transfer to the Hammers after being released by Bolton this summer.

He is West Ham's fourth signing under Sam Allardyce after the arrivals of Kevin Nolan, Matt Taylor and Abdoulaye Faye.

O'Brien said: "Obviously I'm delighted to finally sign because I've been here since the start of pre-season. It's been a few weeks now and it's gone well.

"The manager wanted me to sign and as soon as I heard that, there was no real hesitation."