The former Arsenal man completed his switch to the South Coast on Thursday and he admitted he was delighted.
Lauren admitted the chance to work with Harry Redknapp was a huge draw and his reason to reject other offers, two of which are understood to have come from West Ham and Newcastle.
"I am very excited because it is a new challenge for me and I am looking forward to it," he told Sky Sports News.
"Yes, but first of all I was convinced by the coach. I have also got Sol Campbell and Kanu, in the changing room which is very good."
Glen Johnson is already at the club, but Lauren insists that is not a major problem - as may not play at right-back.
"It is a big challenge for both of us and will improve the team," he continued.
"Whatever, I will happily play in any position and I am just waiting for the first game and if it is Saturday I will be very happy.
"I am looking forward to my first competitive game and I will do my best.
"I am 100 per cent fit and I just need a couple of games."
Lauren admits that it was a wrench to leave Emirates Stadium, but he leaves Arsenal with no regrets.
"I am have been there for six unbelievable years, it is has been fantastic," he said.
"I am very happy and the fans have been fantastic and I will keep them in my heart forever.
"I can now concentrate on my career and look forward.
"I would like to get into Europe [with Portsmouth], it is a good squad with many good players and we can keep winning games."
i still feels that he should be the first choice right back for arsenal. and i thought they going to buy glen johnson?? he is younger and faster.