Can I declare only half of what my (2017) 1099 misc states, since I received the 2nd half in 2018?

My Payer won't draw a new 1099 since they sent the money by the end of December 2017; but I received it late January 2018, and since 2018 will be a frugal year for me, I really would need to declare the second half on my 2018 taxes. Am I allowed to do that?