Jason Blum is astonished that the 'Insidious' franchise has lasted so long.

The 54-year-old producer is involved in the latest movie 'Insidious: The Red Door' and is surprised that the series has continued for five installments after a challenging start.

Asked if foresaw the success of the series, James told JOE.ie: "100 per cent no. When the first one opened, it actually opened to a relatively low number.

"Our partner thought it was a DVD movie and was going to go straight to video and I said, 'I think it's probably a little bit better than that.'

"It's a fair question to ask and neither one of us thought I'd be here talking about this movie 13 years later."

The Blumhouse Productions chief believes that the lack of "high concept" in the franchise – which follows the demon-haunted Lambert family – has helped it become so popular.

Jason explained: "There is no high concept with 'Insidious', it's a great drama about a family that is as scary as hell. On paper, that shouldn't work but I think the magic of the movies is that sometimes you break the rules and audiences connect with them even more and I think that really is true of 'Insidious'."

The new picture marks the directorial debut of Patrick Wilson – who also stars in the movie as Josh Lambert – and he described how it is such a tricky process to create a jump scare.

The 50-year-old star said: "There's so many elements that come together and sometimes don't come together.

"It's not unlike an action movie where you get all these pieces together and you have it in your head but you've got to go in and see what you've really got. That's why the medium is more for directors and editors than it is for actors."