The pair reportedly ended their 18 month relationship last week, and now the Daily Star report the split could cause professional issues as well as personal ones.
Tulisa is set to release her first solo single this summer, but it and other tracks on the album hinge on Fazer's production.
“Fazer was basically masterminding Tulisa’s whole album," a source told the tabloid today. “He’s still planning to be involved but nowhere near to the extent he was supposed to be.
“The first single is done, which should still be out in the spring, but the chances are the album will be delayed now to later in the year.
“They are both understandably finding it hard working together so closely after the break-up.”