Former House Speaker Newt Gingrich says that Donald Trump's five big wins Tuesday night mean the only thing left for establishment Republicans to do is to "get over it" and accept that Trump will be the GOP nominee.

"You see the momentum building here," Gingrich said on Fox News Tuesday night. "I think it'd be very, very hard, virtually impossible, to stop him from winning the nomination at this point."

"This is an enormous achievement building on New York, and means that he's almost certainly going to have an absolute majority of the delegates before you get to the convention in Cleveland," Gingrich added.

Gingrich also laughed off the idea of a contested convention, after Fox host Bill Hemmer showed that Trump now has a likely path to getting the 1,237 delegates needed to clinch the nomination.

"My question to my good friends who talk about a contested convention is, if Trump comes out of California and New Jersey, somewhere, I think Bill Hemmer had him above 1,250 at that point, what's the contest?" Gingrich asked.

"He won," he added. "And the challenge then for the Republican establishment is to get over it."