Coveted striker Dusan Vlahovic completed a 70 million euros ($A111.6m) transfer from Fiorentina on Friday on his 22nd birthday and will wear the No.7 shirt vacated by Ronaldo.

"Today is really a special day for me and one of the most special and happy birthdays I've ever experienced so far," Vlahovic said after Juventus presented him with a cake and candle in the team's changing room at Allianz Stadium.

A Juventus tweet announcing the move included the hashtag "DV7" -- a take on Ronaldo's "CR7".

Vlahovic wore No.9 for Fiorentina.

Juventus said Vlahovic signed a deal until June 2026 and that the transfer fee -- a record in Serie A for a January signing -- includes up to 10 million euros ($16 million) in bonuses.

Vlahovic has scored 20 goals in 24 matches in all competitions for Fiorentina this season and is joint top in Serie A, along with Lazio's Ciro Immobile.

Juventus had struggled to replace Ronaldo since his move to Manchester United in August.

The Bianconeri have scored only 34 goals this season -- fewer than any of the top 10 teams in the Italian top slight apart from Torino.

Vlahovic, a Serbia international, could be the perfect player to change that, having just matched Ronaldo's feat of scoring 33 league goals in a calendar year.

Only three players in Europe's top-five leagues have a better record than Vlahovic's tally of 38 league goals over the past two seasons: Bayern Munich's Robert Lewandowski (64), Borussia Dortmund's Erling Haaland (43) and Real Madrid's Karim Benzema (40).

In an unusual move, Fiorentina president Rocco Commisso announced in October that Vlahovic would not renew his contract with the Tuscan club, which was due to expire in 2023.

That made Vlahovic a hot commodity on the transfer market and he was also targeted by Premier League side Arsenal.

Vlahovic immediately swore allegiance to Juventus -- fifth in Serie A, six points ahead of seventh-placed Fiorentina with a game in hand.

"Juventus represents pride, tradition, family," he said.

"Juventus is always there until the end and never gives up."

Vlahovic could make his Juve debut when they host mid-table Verona on February 6.

Australian Associated Press