The 34-year-old Greek player scored 20 goals in 137 appearances for Bolton since signing from Olympiakos in May 2003.
However he has been without a club since leaving the Reebok during the summer.
He had been training with Hull as a free agent and now joins Phil Brown's Barclays Premier League side on a permanent contract after agreeing personal terms.
He has signed until the end of the season however that could be extended if the move works out.
He told the offical club web site: "I'm very, very pleased to be a Hull City player. My main target and my dream was to stay in England and to stay in the Premier League and Hull City have given me the chance to make my dream come true.
"I am not new to the Premier League. I have been playing in this division for the last five years with Bolton, but I have come to Hull City to make a new start and take another step in my career.
"I have ambitions and I have dreams. I want to help Hull City with all of the strength that I have."
The former Bolton midfielder admits the opportunity to work alongside Phil Brown once again was a major factor in his decision to move to East Yorkshire and he says he owes a debt of gratitude to Brown and City Chairman Paul Duffen.
"Myself and the gaffer have known each other ever since I arrived in England and we have a very good relationship.
"At this point, I would like to thank the gaffer and the chairman for offering me this deal. If those two were not here, maybe I wouldn't have signed.
"The Club is already high in the table and I wish for this place in the table to remain and maybe get better in the future. There is ambition here and a very nice, loud crowd. The team tries to play attractive football and that is one of the reasons I came here."