The Real Madrid midfielder is looking forward to facing his former club on Sunday, and has promised to set aside all of his feelings for the Basque club
The 31-year-old started his career at the Basque club, and represented their first team for five years, before moving to Liverpool in 2004.
"The match against Real Sociedad will be a special one for me, but all feelings will be set aside on Sunday and we'll fight for the win," he was quoted as saying on the club's official website.
"We want to kick off 2013 with a win, but it will be a special match because I have friends that play on the rival team. Also because they're a team who I've supported for my entire life. I have a connection with them, mainly because of my father.
"But now it's time to play the game, we fight for what's ours and all those feelings will be set aside for the match."
The Spain international went on to urge his team-mates to forget their bad run of form at the end of 2012 and recover their confidence as quickly as possible.
"We have to do things right, be a team and feel confident in spite of the poor results," he continued.
"We have to recover that confidence, that fluidity when we play, score the most goals possible and recover those good feelings. Gradually create a solid base for the important games coming up in February and March.
"You have a better year by being professional and looking ahead. Obviously, I'm happy with how things went in 2012, but it's 2013 now and we want to continue celebrating new successes, not resting on our laurels, and win important titles like we did last year."