My client will not issue a 1099-NEC until after April 15th. How do I file this income on my taxes?

Due to a client accounting error, my client will not issue a 1099-NEC until after April 15th. How do I file this income on my taxes? Do I include it as 1099-NEC (knowing that the form is coming), or include it as income not reported on a 1099-NEC?