Derby have given Chelsea permission to speak to Frank Lampard about the vacant managerial position at Stamford Bridge, the Sky Bet Championship club have announced.
Lampard, the Blues' record goalscorer, has been strongly linked with the job since Maurizio Sarri left the role this month.
A statement issued by Derby read: "Derby can confirm they have granted permission for Chelsea to speak to Frank Lampard about the vacant managerial position at Stamford Bridge.
"With pre-season fast approaching for both clubs it is hoped this will allow Chelsea to swiftly conclude their discussions. The club will make no further comment until it is appropriate to do so."
Derby reached the Championship play-off final under Lampard, losing 2-1 to Aston Villa at Wembley last month.
While missing out on promotion was hugely disappointing, it represented a good first season in management for the 41-year-old, who has since been in talks about a new contract with the Rams.
Chelsea would have to pay compensation to take Lampard away from Pride Park as he has two years remaining on the deal he signed last summer.
The former England midfielder made 648 appearances for the Blues, scoring 211 goals and winning 11 major trophies.
If he does take over at Stamford Bridge, he will inherit a transfer embargo after Chelsea were given a two-window transfer ban by FIFA - a decision the club are appealing against at the Court of Arbitration for Sport.