The French outfit's all-new driver lineup intensifies speculation that Heikki Kovalainen will indeed move to McLaren to fill the seat vacated by Alonso after just one year of his curtailed contract.
Renault also said French-Swiss rookie Romain Grosjean, the reigning 2007 F3 Euroseries champion, will replace Piquet as test driver next year.
The statement did not mention the term of the former double world champion's new deal, but reports indicated either a one or two-year contract.
The Enstone based team's 2008 car will be launched at Renault's corporate communications headquarters in Paris on 31 January, a week after the R28 is tested for the first time in Spain, Renault also revealed.
Alonso, 26, said: "I would like to thank all the other teams for their interest to have me work with them."