The 38-year-old and Dan, 31, have been together for seven months and he allegedly proposed on Friday night.
KYM MARSH RANTS AT 'SICK TROLL' WHO STOLE DAUGHTER'S PHOTO AND SET UP FAKE FACEBOOK PROFILE
Personal trainer Dan took Coronation Street actress Kym to a Manchester hotel to pop the question, before whisking her away on a romantic break.
A source told The Sun: "He knew it had to be perfect for Kym. He was pretty certain she'd say 'Yes' but he was still nervous. Dan hadn't told Kym what was going to happen but they both dressed up for a big night out.
"Even though they haven't been together long, they both know it's completely right. A lot of Kym's friends were worried to begin with that she might be rushing into something with Dan.
"But now they've got to know him they're convinced he's a nice guy with only good intentions."
Kym has been married twice before, to EastEnders actors Jack Ryder and Jamie Lomas, who she has daughter Polly with. She also has two teenagers from another relationship.
Dan has four-year-old daughter Lexi-Grace from his relationship with Hollyoaks actress Stephanie Waring.
The source added: "Obviously there are a lot of complications because of their ex-partners, but they feel if they're together they can overcome anything."
Although Kym and Dan have yet to publicly confirm the news, the former Hear'Say singer took to Twitter on Friday to share a loved-up snap of them