Charlton have signed defender Greg Halford and Lee Cook on loan deals until the end of the season.
Halford is changing clubs for the third time in 12 months
It is the third time Halford has moved in the last 12 months, having gone from Colchester to Reading last January and then to Sunderland in the summer.
"I think he's got a lot to prove," boss Alan Pardew told the club website.
Left-sided midfielder Cook joined the Cottagers in the summer for £2.5m from QPR but has yet to make an appearance because of injury.