Lord Sugar's aide admitted that he missed working alongside Mountford on the BBC One show and had failed to connect with her replacement Karren Brady in the same way.
"Ah, the blessed Margaret. I think she's very special," Hewer told the Daily Mail. "It may have something to do with the length of time I've known her... It may be because we're nearer in age. It may be because we've shared experiences when working for Sugar.
"But Karren's no slouch. We have a cordial relationship... We're different ages and from different backgrounds. Karren's got her children, her husband, her own set.
"Margaret and I used to go out to dinner because both of us were kicking around London on our own. We were two lonely old people with white hair and we bounce off each other quite well mentally."
Hewer also commented on Mountford's decision to quit The Apprentice after the fifth series in 2009 to finish her PhD in papyrology.
"I think Margaret genuinely had to get on with her PhD," he argued. "I don't think she was as attracted to the money as much as me. She made a lot more as a lawyer than I did."
Hewer previously claimed to be "heartbroken" by Mountford's Apprentice exit.
The Apprentice series seven final, which will feature a guest appearance from Mountford, airs tonight at 9pm on BBC One.
> Nick Hewer picks 'Apprentice' winner
> DS Icon: Nick Hewer & Margaret Mountford
> Nick Hewer praises "genuine" Karren Brady