Two high-profile actors were spotted in action in Watford today with residents suggesting it may be the new instalment in a popular horror franchise.

Stars Patrick Wilson and Vera Farmiga were both seen filming in Cassiobury Park, accompanied by several crew members, in what excited onlookers speculated was for upcoming film The Conjuring: Last Rites. 
A-list actors Patrick Wilson and Vera Farmiga on set in Cassiobury ParkA-list actors Patrick Wilson and Vera Farmiga on set in Cassiobury Park (Image: Donald McDougall)Wilson can be seen rocking a slick back haircut, suit and black trench coat with a large black notepad while Farmiga donned a velvet French coat, scarf and leather gloves. Both appear in The Conjuring trilogy first released in 2013.

Other images show a black hearse tailed by a limousine of a similar colour alongside some damp camera equipment.

Two black vehicles and some rather damp camera equipment.Two black vehicles and some rather damp camera equipment. (Image: Donald McDougall) It comes after residents spotted 25 gravestones in a cordoned-off section on Saturday (September 28), while over a dozen caravans and support vehicles appeared in the car park.

What is being filmed has not been officially confirmed, although before the latest pictures emerged it had been suggested to be an American horror film.

Two locals were reportedly told by the site staff it was Warner Bros filming for the fourth film in The Conjuring franchise, which is due to be released next year.

(Image: Donald McDougall)

However, another claimed they had been told it was the third instalment in the 28 Days Later zombie film series, which is also set for a 2025 release.

The filming also took place on Sunday and is thought to continue until tomorrow (October 1). Watford Borough Council confirmed the Cassiobury filming was for Mammoth Productions.