Star of the "X-Men" films and "The Lord of The Rings" trilogy movies Sir Ian McKellen is about to embark on another iconic role, as the super-sleuth Sherlock Holmes.

McKellen is very active on social media: Facebook and Twitter. He released this week a photograph of himself via Twitter in full make-up and costume as the titular detective. "Mr. Holmes" is the name of the film. McKellen, 75, wrote on Twitter: "Over 70 actors have previously played Sherlock Holmes. Now he's 93 years old and it's my turn. #MrHolmes."

McKellen as Mr. Holmes and the related film project was mentioned early on this year, but even more has been revealed now: who is involved, what is the story about, and when can we expect the return of Sherlock Holmes.

Directing "Mr. Holmes" is Bill Condon. This is a near 20 year reunion of sorts for McKellen and Condon; Condon had directed McKellen in "Gods and Monsters" in 1998, Screen Daily reported.

The original title of the Sherlock Holmes film was "A Slight Trick of the Mind," which is based off a 2005 novel of the same name. The book was not written by Sir Arthur Conan Doyle but by Mitch Cullen; Jeffrey Hatcher will be writing the screenplay for this book-to-film adaptation.

The "Dreamgirls" and "Kinsey" writer and director, Condon, will also be reuniting with Laura Linney in "Mr. Holmes." Linney worked with Condon in "Kinsey," "The Fifth Estate" and on the series pilot of "The Big C" in which Linney starred, Screen Daily reported. Linney is expected to play Mrs. Munro, Sherlock's housekeeper, who he tells the tail of his last case to, along with her son, played by Milo Parker.

The aforementioned Parker, will be joined by Patrick Kennedy, who starred in films such as, "War Horse," "Atonement," and the upcoming Pierce Brosnan film "The November Man." Also in the cast, is the rising dramatic and science-fiction star Hiroyuki Sanada of "The Last Samurai," "The Wolverine," "Lost," "Helix," "Revenge," and the new CBS TV series "Extant."

Deadline reported that Sanada will be playing Umezaki, a snappy botanist who McKellen's Holmes visits in Japan.

Also in the cast are: Hattie Morahan of "The Golden Compass," Roger Allam of "Game of Thrones," "Endeavour," and "V for Vendetta;" also Philip Davis of "Notes on a Scandal," and "Bleak House," along with Frances de la Tour "Harry Potter and The Deathly Hallows: Part 1," "Alice in Wonderland," and the British TV series "Vicious."

"Mr. Holmes," which is expected to follow the novel, takes place towards the end of WWII. Holmes has long since retired to his home in Sussex, to a life of beekeeping. As Holmes ages, he is frustrated by the fact that he has difficulty remembering things. Holmes believes that the bees' royal jelly is his secret to his longevity; his research of the aging process takes him to post-war Japan, Empire reported.

While in Japan, Holmes meets and encounters the son of a former British diplomat who knew him, but whose father had disappeared at the start of WWII. For Holmes, despite his dwindling memory, the disappearance of the boy's father has the recognizable lure of an unsolved case, Empire reported.

McKellen is very excited about the role and to be working with Condon once again. "Sherlock Holmes at 93 is retired [and] still solving mysteries ... So many splendid actors have already played the part but none of them had Bill Condon directing. I'm the lucky one: and I'm excited," Screen Daily reported.

"Mr. Holmes" is expected to debut in early 2015.