The forward, who scored 10 goals and assisted 12 in the Bundesliga last season, is currently with Brazil at the Copa America in Chile, but the Reds have managed to sign the 23-year-old, beating reported competition from the likes of Manchester United along the way, according to the Independent.
It should leave the Anfield faithful eagerly following the rest of the tournament, with Philippe Coutinho also involved alongside his new club teammate.
Is Firmino the signing of the summer so far?
He is certainly rumoured to be one of the most expensive transfers this close season at £29 million, according to BBC Sport.
With Neymar suspended for the rest of the Copa America tournament after an attempt to headbutt Colombian defender Jeison Murillo at the end of the 1-0 loss to their South American neighbours, it is Firmino who will be given the opportunity to star in his place in the country's famous yellow and gold.
Liverpool's new forward has already scored 4 goals for Brazil in the last 8 months since making his debut, and he netted what proved to be the decider in the recent win over Venezuela to ensure qualification for the quarter finals.
If Brazil win the tournament, with Firmino playing an important part in that triumph, it is likely the attacker would have had plenty of other interested admirers, not to mention costing the Reds significantly more to bring to Anfield.