Britney Spears' upcoming tour has been thrown into doubt after the singer threatened to pull out unless her sons can join her on the road, according to a new report.

The singer has reportedly said she will drop out of all 33 concerts unless her boys Sean Preston and Jayden James can accompany her across the US.

Britney's dad and conservator Jamie is said to be in negotiations with her ex-husband Kevin Federline - who has custody of their sons - about having three homes set up in New Jersey, New Orleans and L.A for both the boys and K-Fed while Brit is on the road.

Furthermore, K-Fed has also been offered a whopping $4000 a week for his co-operation, according to TMZ.

Meanwhile, K-Fed's lawyers are reportedly livid that negotiations took place without their appropriate input.

Britney's tour kicks off in New Orleans on March 3.

Earlier today Entertainmentwise reported that Brit and the wannabe rapper are allegedly attempting to salvage their relationship by moving in with one another.

See Britney and her boys below