The pair were recently spotted jogging together, but supermodel Heidi insisted that Kim didn't spill the beans about what she is planning to wear to marry fiancé Kris Humphries.
'Everyone wants to know what she's gonna wear,' Heidi told E! Online. 'I don't know!
'I'm sure she's gonna find something beautiful. She has good taste and she loves clothes.'
Talking about her fitness regime, 38-year-old the mother-of-four said that jogging is the key to her slim figure.
'Lately, I've just been running. I run four miles a day. Last year, I did 120 miles in seven weeks,' she said.
'I have this little FitBit I attach to my clothes that counts all the calories and steps I do,' she explained.