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Nina Dobrev has quit CW's The Vampire Diaries after six years playing Elena Gilbert Reuters

Actress Nina Dobrev left fans heartbroken when she announced she had quit The Vampire Diaries but before rumours suggest she was fired, sources insist that it was entirely the star's decision.

The 26-year-old announced her departure from the popular CW show via Instagram, describing the past six years, during which she played Elena Gilbert, as "the journey of a lifetime".

Actor Michael Trevino, who has played Tyler Lockwood since season one, also announced he was leaving the series.

Explaining Dobrev's decision to quit, a source has told E! News that her departure has "been in the works for quite some time" and that it was "truly [Dobrev's] choice". The website adds the actress was ready to "reclaim her freedom" and move on to other roles.

Some fans are concerned the departure of two of the main stars could mean the end of the series but network CW has confirmed the show will go on, with actor Ian Somerhalder still in his lead role.

Dearest TVD Family, I've just spent the most beautiful weekend on Lake Lanier in Georgia with my own TVD Family, the cast and crew of The Vampire Diaries. I want to be the first to tell you that it wasn't just a holiday celebration, it was a goodbye party. I always knew I wanted Elena's story to be a six season adventure, and within those six years I got the journey of a lifetime. I was a human, a vampire, a doppelganger, a crazy immortal, a doppelganger pretending to be human, a human pretending to be a doppelganger. I got kidnapped, killed, resurrected, tortured, cursed, body-snatched, was dead and undead, and there's still so much more to come before the season finale in May. Elena fell in love not once, but twice, with two epic soulmates, and I myself made some of the best friends I'll ever know and built an extended family I will love forever. There's more to come before we wrap this up, and I promise you'll get to hear all about my experiences over the next month as we approach the season finale (I have given an exclusive interview for the June issue of SELF Magazine that I am excited for you to see!), but until then I invite you to hop on the roller coaster ride that is Elena Gilbert's life and join me as I celebrate her and prepare to say goodbye to her -- and to my work family -- as I move on to the next chapter of my life. I want to share this goodbye with all of you (this weekend's pictures were just the beginning). You, the wonderful fandom who gave more love, support and passion than anyone could have ever imagined seven years ago, when a young Degrassi girl from Canada showed up in LA to audition for 'that Twilight TV show.' ;-) I love you all. Fasten your seatbelts. If you think you know what's coming, you don't. Love, Nina

A photo posted by Nina Dobrev (@ninadobrev) on

The Vampire Diaries' executive producer, Julie Plec, said in a statement released to Variety: "Saying goodbye to Nina is both bittersweet and beautiful. After six-plus years together, the entire cast and crew of The Vampire Diaries has reached a level of closeness that I don't think any of us ever expected.

"Nina is excited to spread her wings, get some rest, travel the world and also take it by storm, and we support her a thousand-fold. We will miss Nina and the four hundred characters she played, but we look forward to the insane and exciting challenge of continuing to tell stories of our Salvatore brothers and our much-loved and gifted ensemble."

News of Dobrev's departure may not come as a surprise to some as reports surfaced in August 2014 that one of the main cast members had not signed on for season seven.

It is not just the on-screen storylines that have gripped loyal viewers over the years, they also invested in the real-life romance between co-stars Dobrev and Somerhalder but they split up in 2013 after three years of dating.

So long, Dobrev. Here are some of the most heartbreaking reactions from devastated fans: