Five-cap Williams was selected for Wales' 2008 tour of South Africa
Wales scrum-half Andy Williams will remain with Gloucester for the season, having originally joined from Moseley on a short-term loan over Christmas.
The five-cap 28-year-old has previous experience with Bath, the Ospreys and the Dragons.
"He will be with us initially until the end of the season and we'll see where things go from there," said Gloucester coach Bryan Redpath.
"We were looking a bit thin in the scrum-half position."
Williams parted acrimoniously with the Dragons last January before finishing the season with Cardiff RFC in the Welsh Premier.
The Swansea man moved to Moseley at the start of the current season, agreeing a deal whereby he could leave the club if he gained a Magners League, Guinness Premiership or French Top 14 contract.
"Andy's an experienced campaigner," said Redpath, who will lose Rory Lawson to Scotland and Jordi Pasqualin to England Under-20 over the coming months.
"He's an international who has also played a significant amount of Heineken Cup rugby so he knows all about performing at the highest level."