Norwegian international Johansen leaves Celtic

The 25-year-old - who has scored 20 goals in 114 appearances for Celtic since joining from Stromsgodset in 2014 - agreed to the move after failing to get the terms he wanted on a new contract at the Scottish side.

"I think he (Johansen) has always wanted to play in England, so the opportunity has come for him," said Celtic manager Brendan Rodgers.

"He wasn't going to sign a new deal, so it's one that probably works well for both really".

Johansen, who won three Premiership titles and was Scottish footballer of the season in 2014/15, will probably not be the last former first-choice player to leave the club as Rodgers seeks to strengthen the squad for the Champions League group stage.

Celtic have been drawn in a tough group alongside Barcelona, Manchester City and German outfit Borussia Moenchengladbach.

Players such as Honduran international full-back Emilio Izaguirre, who has been at Celtic for six years, Nigeria defender Efe Ambrose and former Scottish international midfielder Kris Commons are also thought likely to leave.

"There's been a number of enquiries about our players," Rodgers said.

"There's a number of players that are fully aware of where they stand and they know they will struggle to get games.

"So I think between them and their agents, they are obviously looking to get moves that will allow them the possibility to play".