The former Pussycat Dolls are both judges on UK reality TV shows - with Kimberly on 'Got to Dance' and Ashley on 'Dancing on Ice' - and the former bandmates, who are both from the US, have become even closer as a result.
Kimberly said: ''I've been so thankful to have Ashley over here in the UK. She's probably my closest friend.''
The 30-year-old star also admits she had a scary time recently when one of her decisions on 'Got to Dance' was booed by the audience.
She added: ''It was terrifying. My whole body was shaking afterwards. I disagreed with the comments judges Aston [Merrygold] and Ashley [Banjo] were giving. There can be some heated debate on the panel, but you're not always going to be right. I'm learning that.''
However, Kimberly said she has become a huge fan of choreographer Ashley since they've worked on the show.
She added to Closer magazine: ''We've become really good friends and I'm really proud of Ashley and his group Diversity. The fact a dance troupe can sell out arenas is amazing.''