Portsmouth made a double swoop for Manchester City defender Tal Ben Haim and Benfica midfielder Hassan Yebda on Tuesday.
Israel international Ben Haim has agreed a four-year contract and his free transfer will be rubber-stamped once he has been given a work permit.
The 27-year-old, who made just nine starts for City following his switch from Chelsea last year, could make his debut against Bolton - another of his former clubs - on Sept. 12.
Ben Haim joins a team who are bottom of the Premier League after four successive defeats but he is determined to help them climb out of the relegation zone.
"It is a big challenge because after four games we have no points but I am ready for the challenge," Ben Haim told Portsmouth's website.
"I want to help Pompey get some good results and take them to the position they belong in.
"We've bought a few players in now and I believe we can turn things around and win some games."
Pompey boss Paul Hart also landed Yebda from Portuguese club Benfica.
The 25-year-old French-born Algerian has moved to Fratton Park on a season-long loan.
He began his career with Auxerre and has also had spells at Laval and Le Mans.