Gillian Anderson says she struggles to see Jamie Dornan in anything other than his birthday suit because of his Fifty Shades role.
"I could only see him naked from the moment he walked in. It was really distracting," the actress joked.
A film based on the hugely successful book is due out in February 2015 with Dornan playing Christian Grey.
"The movie hasn't even come out - he might suck," Anderson said when asked about the anticipation surrounding it.
Jamie Dornan is playing a very different role with Gillian Anderson as series two of The Fall begins.
The BBC Two drama sees Anderson star as a detective on the hunt for serial killer Dornan.
During the first series of show the pair only had a handful of scenes together.
Yet Jamie Dornan says the chemistry between them is undeniable, even though most of their on screen contact, was by phone.
"I think that it's so clever. The fact that there is such chemistry and it's done through any lack of physical contact."
According to figures around 4.5m viewers a week tuned in to watch The Fall.
"It's just down to great writing, very smartly crafted," he added.
Gillian Anderson, who became an international star, with her role as Special Agent Dana Scully in The X-Files says series two will see the pair share much more screen time.
Given the storylines The Fall deals with, Jamie Dornan says it was important there was some light relief while filming.
"On a general level it's a pretty fun set. It's the same crew as the first series. So we are like a big family," the actor said.
Dornan, 32, confessed the light relief was provided by him - even if no-one else laughed.
"I'd love to be known as a prankster but no, I'm not hiding stuff in Gillian's trailer or anything like that.
"But I like to have a laugh. I can get very silly and make jokes. Which are not funny to anyone but me," he giggled.
The Fall starts on Thursday night on BBC Two at 21:00 GMT