Derby have completed the signing of striker Johnny Russell from Dundee United for an undisclosed fee.

Russell has signed a four-year contract with the Rams after undergoing a medical at the Championship club on Monday.

A fee was agreed for the player, who scored 20 goals in 38 appearances for the Scottish Premier League side last season, last week and the 23-year-old becomes Derby's third summer signing after the arrivals of Lee Grant of Burnley and Chris Martin.

"We're delighted to sign Johnny and his goalscoring exploits north of the border are something we've been aware of for some time," Rams boss Nigel Clough told the club's official website.

"He's been prolific in the last few years and from what we've seen of him we believe he can transfer that form to the Championship.

"At 23 he is a player who's only going to improve as well and we feel he's the right type of player to complement the options and players we already have in attack.

"We've had some stiff competition from a number of clubs to get him here so it's nice to come out on top and convince him Derby County is the best place for him.

"Johnny is an ambitious and hungry player and he shares our desire to be fighting it out for a top six spot next season and we're pleased to have him on board."