Charlton have made Eggert Jonsson their third signing of the day.
The 24-year-old has signed on a 28-day loan deal from fellow npower Championship club Wolves.
His signing follows the deals completed for defender Dan Seaborne and former Fulham midfielder Courtney Harris earlier in the day.
Boss Chris Powell told the club's official website: "I just felt I needed to boost the midfield area.
"We need to have players that have games behind them and Eggert comes into this category.
"He's a centre midfielder who keeps things simple and ticking over."
The Iceland international goes straight into the squad to face Bristol City on Sunday.