The Hollyoaks stars ended their relationship last November after two years. However, since the break-up, the pair have been spotted in public together several times, sparking rumours that they had rekindled their romance.
Speaking to Closer, Whittle insisted: "I think Carley's lovely, but I'm still single. We're still mates and always will be - she's my best friend. People think it's hard to be friends with an ex, but when the person is her I don't think we could ever not be."
The Strictly Come Dancing runner-up said that he is not currently looking for a girlfriend because he is concentrating on his career.
Of his popularity with female fans, he commented: "You get propositions every other day, but it's not real. They don't like me, they like the character they see on TV. I don't want to sound like I'm complaining, but it can be a very lonely business."
Whittle filmed his final Hollyoaks scenes earlier this month.