Girls Aloud star Nadine Coyle is reportedly worried about the group's reunion.
Cheryl Cole, Nadine Coyle, Sarah Harding, Nicola Roberts and Kimberley Walsh will this morning officially announce their comeback plans in a special announcement online.
At 10AM the group will stream a live event to fans around the world as they reunite for the first time in three years.
The group have already confirmed a new single, Something New, which is expected to be this year's Children In Need track.
The girls are also expected to confirm they'll be releasing a new album and planning a new tour.
But having spent the last three years apart, sources claim it could be a rough reunion.
The five girls have all tried various solo projects, with differing degrees of success.
And while some of the group - like Cheryl, Nicola and Kimberley - have remained in close contact, others haven't even been in the country.
A source said: "Nadine knows that the other four girls are closer to each other than they are with her. Now they're going to have to spend so much time together. It's stressing her out."
Speaking to Closer magazine, the supposed insider claimed: It's not been great between Nadine and the others for ages.
"Things have been strained as he's been in LA for the last four years and has missed everything that has been going on in their lives."
However Nadine has been with the girls more recently, appearing on Strictly Come Dancing to support Kimberley and also at the O2 Arena to watch Cheryl's solo tour.
Listen to Girls Aloud's new single Something New below...