St Etienne have made Norwegian midfielder Ole Selnaes their fourth signing of the transfer window.
Alexander Soderlund, Oussama Tannane and Franck Tabanou have already joined Les Verts in January and the Ligue 1 club on Monday secured 21-year-old Selnaes on a four-and-a-half-year contract.
After leaving Rosenborg to move to the Stade Geoffroy-Guichard, Selnaes told asse.fr: "Alexander Soderlund is a good friend of mine and we have chatted about St Etienne.
"He talked the club up and told me that everyone was happy here. He also told me about the good atmosphere and great fans.
"I can certainly say I've never seen fans like this before and I really can't wait to get started."
St Etienne fans had an opportunity to watch their new left-footed defensive midfielder Selnaes in action when Rosenborg visited the Massif Central for a Europa League encounter in September.