The cast of seminal television series The Sopranos reunited to mark the show’s 20th anniversary.

David Chase’s groundbreaking mafia drama first aired in the US on January 10 1999 and viewers spent six seasons following the trials and tribulations of New Jersey mob boss Tony Soprano, played by the late James Gandolfini.

The Sopranos has been named by many critics as the greatest TV show of all time and is credited with paving the way for more mature series on the small screen, including The Wire, Breaking Bad and Game Of Thrones.

HBO’s The Sopranos 20th AnniversaryEdie Falco, from left, Jamie-Lynn Sigler and Robert Iler attend HBO’s The Sopranos 20th anniversary event (Charles Sykes/Invision/AP)

On Wednesday, cast members Edie Falco, Jamie-Lynn Sigler and Robert Iler were among those to gather in New York to celebrate the landmark.

US actor Gandolfini died at the age of 51 while on holiday in Rome in 2013. Falco, who played Tony’s long-suffering wife Carmela, spoke about the HBO show’s anniversary and Gandolfini’s absence.

Speaking to Variety, she said: “It feels very weird. First of all, that it’s 20 years, that’s crazy. And not that I don’t think of Sopranos, but when I do, I almost feel like it’s a dream I had.

“It’s a very private relationship with that chapter of my life and then here I am with cast members and realising that they all have a private relationship with it and when we get together it becomes very much alive and it becomes so obviously wrong that Jim (Gandolfini) isn’t here.

HBO’s “The Sopranos” 20th AnniversaryMichael Imperioli, left, and Tony Sirico attend HBO’s The Sopranos 20th anniversary event (Charles Sykes/Invision/AP)

“Which is not something I think of on a daily basis, but obviously he was a integral part of the show but also of the alchemy of our cast. It’s a very unusual, very rich experience, being here tonight.”

The Sopranos, created by Chase, tells the story of local mafia boss Tony, who has to balance his criminal activities with family life.

The story is often explored through visits to psychiatrist Jennifer Melfi, played by Goodfellas actress Lorraine Bracco.

HBO’s “The Sopranos” 20th AnniversarySteven Van Zandt and Maureen Van Zandt, were among the stars attending The Sopranos’ 20th anniversary event (Charles Sykes/Invision/AP)

Also attending the anniversary event were Michael Imperioli, who played Christopher Moltisanti, Tony Sirico, who played Paul ‘Paulie Walnuts’ Gualtieri and Steven Van Zandt, who played Silvio Dante.

When The Sopranos ended after eight years in 2007, many viewers were left angered by its notoriously abrupt ending, which leaves the fate of the Soprano family a mystery.

However Falco said she is a fan of Chase’s decision not to provide closure.

She said: “What David Chase said at some point is that their lives continued to go on, whatever that was, it’s just that we weren’t privy to it anymore, as audience members.

“So everyone has different theories about what it meant and I love that.”

A Sopranos prequel, titled The Many Saints Of Newark, is in development.