Ryan Reynolds has started filming 'Deadpool 2'.

Ryan Reynolds (c) Instagram

Ryan Reynolds (c) Instagram

The 40-year-old actor has reprised his role as the titular anti-hero in the second instalment of the fantasy film, and the Canadian hunk has announced on social media he has already finished shooting the first set of scenes for the production.

And Reynolds - who has daughters James, two, and nine-month-old Ines with his wife Blake Lively - feels "good" slipping back into his red, skin-tight, full-body costume to portray Wade Wilson and his alter-ego in the follow-up film.

Alongside a photograph of the clapperboard on his Instagram account, which revealed it was the first take, on the sixth roll shooting the scene "2.7", he wrote: "The sun sets on day 1. Feels good to be back. This dog can hunt. (sic)."

And in preparation for his comeback, Reynolds has been undergoing gruelling fitness sessions with his personal trainer Don Saladino to help him get back into shape for the action movie.

The exercise guru previously shared a video on his photo-sharing site, which captured Reynolds working up a sweat as he focused on toning up his abs.

Saladino captioned the video: "@vancityreynolds performs one of his favorite ab exercises in preparation for #deadpool2 (sic)."

Although the plot for 'Deadpool 2' is not widely known, the film will see the return of Stafan Kapicic as Colossus, Brianna Hilderbrand as Negasonic Teenage Warhead, as well as Morrena Baccarin who portrays Reynolds' on-screen love interest.

Josh Brolin is set for a busy year ahead as he has been cast as mutant Cable in the production opposite Reynolds, as well as the evil villain Thanos in the upcoming 'Avengers: Infinity War'.

And the 49-year-old actor's latest venture has surprised his co-star Reynolds because it means Brolin plays two characters in the Marvel Cinematic Universe.

Speaking about his colleague's latest venture, Reynolds said: "The f**k, Fox! You can't play 2 characters in the same universe!! Josh Brolin was in 'Sicario' and I was in 'Sabrina The Teenage Witch'. (sic)"

'Deadpool 2' will be directed by David Leitch and the sequel is slated to be released in June 2018.