Mane sealed the move after scoring 25 goals 75 appearances in two seasons with the Saints.

With additional incentives potentially increasing the fee, Mane could eventually become most expensive signing in Liverpool's history, eclipsing the $63 million sum paid for Andy Carroll from Newcastle United in 2011.

"Today is a big day and I am very happy to sign for one of the biggest clubs in Europe," Mane told Liverpool's official website.

"It's a club that has won a lot of trophies and has a big history.

"Now I am looking forward to meeting all the staff and my teammates and starting the season."

Mane treads a now-familiar path from St Mary's Stadium to Anfield, having become the fifth player in three season to join the Reds from the Saints after Rickie Lambert, Adam Lallana, Dejan Lovren and Nathaniel Clyne.

The Senegal international scored in all three of his appearances against Liverpool last season, including the late winner in March's 3-2 success at St Mary's Stadium.

Jurgen Klopp has already added defender Joel Matip, midfielder Marko Grujic and goalkeeper Loris Karius to his ranks for next season.

Mane's Southampton departure sees him follow Victor Wanyama – who joined Tottenham – out of the exit door and comes after manager Ronald Koeman left the club to take charge at Everton.