The 24-year-old has previous experience in the Premier League having spent three seasons at Liverpool, and he is excited at the chance to play in the top flight once again.
"It was not a surprise for me, it's a good opportunity for me to join a good club in the Premier League showing interest in me," PA quotes Ngog as saying.
"I was really pleased to get the chance, I thought about it and decided to sign here. I was a part of Bolton, I was not talking to any other clubs but as a player you want to play in the Premier League and that is why I made the decision.
"It's for others to say if I am a Premier League player but my challenge is to help the team win as many games as I can. The objective is to stay up and to do that we have to win games."
Ngog, who has joined the Welsh side until the end of the season, will be eligible for tomorrow night's match against Fulham.