ALVIN AND THE CHIPMUNKS family sues 20th Century Fox for nuts – uh – profits from the top grosser.

The popular film about the misadventures of three singing chipmunks is the nexus of a legal battle over who rights to the franchise that’s spawned millions.  

The Bagdasarian Family execs are suing 20th Century Fox to force them to hand over half the profits from the film.

The lawsuit say that screenwriter Linda Karman, who is married to the son of Ross Bagdasarian who created Alvin as a novelty record in the 1950s, charge the Squeakquel producers of suing unauthorized portions of a script she wrote.

 The script was rejected but then portions used anyway, the suit alleges.

"Karman’s provision of her screenplay writings to Fox was conditioned upon the payment of adequate compensation for those writings and her attendant services, which Kamen never received," the complaint reads.

But Fox studio execs are planning to do battle, saying it is "completely without merit … and in the meantime, we are continuing to move forward with this franchise."

The plaintiffs want Karman made a co-owner of the script, arguing she should receive half of all profits "attributable to The Squeakquel’s screenplay".

The live action animated hit netted more than $442 million at the box office, worldwide.