Andre-Villas Boas has made Gylfi Sigurdsson his first signing as Tottenham Hotspur head coach.
The former Chelsea manager was only appointed as Harry Redknapp's successor on Tuesday, but has moved quickly to bring the Hoffenheim midfielder to White Hart Lane.
The move secures Sigurdsson's return to the Premier League, where he impressed so much during the second half of last season on loan at Swansea City.
The 22-year-old netted seven times in 19 appearances for the Welsh side and picked up March's Player of the Month award.
Sigurdsson had looked to turn his successful loan spell into a permanent move after Swansea settled on a record-breaking £6.8million fee with Hoffenheim.
The Swans also announced that personal terms had been agreed, but manager Brendan Rodgers' move to Liverpool saw the move falter.
Sigurdsson had been linked with a move to the Reds to rejoin his former manager, but Spurs have today swooped to compete the signing of the in-demand midfielder.
Sigurdsson spent loan spells at Shrewsbury Town and Crewe Alexandra as he looked to establish himself in the Royals' first-team, where he became a key player in the 2009/10 season.
The midfielder won the club's Player of the Year award in what was his only full season for the Berkshire outfit, who sold him to Hoffenheim at the start of the following campaign.
The midfielder enjoyed a good start to life at the Rhein-Neckar Arena, but fell down the pecking order and was farmed out on loan to Swansea in January.