Liverpool FC have officially opened the stadium's new Main Stand, increasing the overall capacity to 54,074.
The £100m expansion work has added a third tier for supporters, boosting Anfield's crowd capacity by about 8,500.
Work began on the stadium last year and the club said it marked another "incredible chapter".
The expansion work is part of a wider £260m regeneration of the Anfield area of the city
The redeveloped stand now houses about 20,500 seats and is the new home for the Hillsborough memorial.
Manager Jurgen Klopp said "it's so impressive" and "one of the nicest stands" he has ever seen in his life, adding that it "should be an advantage" for the team.
He urged fans to make lots of noise at the first game in the newly expanded stadium on Saturday when the Reds host Premier League champions Leicester.
Club owner John W Henry had a tour on Friday along with LFC legends Kenny Dalglish, Ian St John, Ian Rush and Jamie Carragher.
Two public spaces near the stadium were renamed 96 Avenue and Paisley Square last month in memory of the Hillsborough victims and former Reds manager Bob Paisley.
The Hillsborough memorial has been repositioned in 96 Avenue after being moved for 18 months to Liverpool Cathedral while the work was finished.
Further work is planned on the Anfield Road Stand to add a further 4,800 seats and bring capacity up to 59,000.