Reports this week suggested that Blue had only signed up for four dates as they felt they were too big for the jaunt. However, it is just that the group have "prior commitments" on the other dates, Heaton told PA.
She said: "Blue are doing four dates - they are not doing the other dates because they have prior commitments. It's not because they are too big - they wish! I love the boys.
"The stories about them being too big for the tour is not from their camp. I don't think the boys said that, so don't believe one word of it."
Blue will appear at dates in Aberdeen, Liverpool, Nottingham and Bournemouth.
The boyband will release their new studio album Roulette on April 15 before headlining their own show at London's Shepherd's Bush Empire on May 3. They have their own tour planned for September.
Meanwhile, Heaton spoke about Liberty X's decision not to record new music in the wake of their appearance on the ITV2 series.
"We talked about it, and we thought we've got so many children between us and quite a few things individually going on that we didn't want the pressure to be successful again. We just wanted to have fun," the 33-year-old said.
She added: "I know some of the other bands are planning to release new material but Liberty X, we are not planning to do that. We are just enjoying it for what it is.
"We're going to enjoy the gigs, all the performing and have fun and not take it too seriously - and know at the end, we go back to being mums and dads to our children. That's how it's different."
The Big Reunion UK arena tour kicks off in Sheffield on May 3.
Watch Liberty X's music video for 'Thinking it Over' below: