Liverpool have been charged by the Premier League with making an illegal approach for former player Christian Ziege while he was at Middlesbrough.
Ziege, the German international defender now at Tottenham, has also been charged in connection with the transfer.
Both the Anfield club and Ziege have been given 14 days to respond to the charges, and are likely to face a Premier League disciplinary commission.
The charges follow a complaint from Middlesbrough over the transfer of Ziege to Liverpool for £5.5m at the start of last season.
The charges follow a 10-month investigation into allegations made by the Teesside club, and are a severe embarrassment to Liverpool and manager Gerard Houllier, who last year described Middlesbrough's claims as "laughable".
A Premier League spokesman said: "I can confirm that Liverpool and Christian Ziege have been charged by the Premier League.
"Both parties have 14 days to respond. They can either admit their guilt and cite mitigating circumstances, in which case a commission drawn from the Premier League disciplinary panel will be set up.
"Alternatively they can plead not guilty and a similar commission would be drawn up."
The League spokesman said the charges related to "approaches made to a player registered to another club, without the permission of that club, via his agent."
If the charges are proved, Middlesbrough will seek compensation for a player they valued at £8m.