Even election jitters: Trump congratulates his candidate in California primary

"Congratulations to Steve on coming in first place," Trump wrote on social media, adding that Hilton is a "winner" who will "turn around" the state quickly.

As of early Thursday, with 56 percent of the vote counted, according toNPR, Hilton, a British immigrant and former Fox News anchor, had 27.6 percent support. Democrat and former Health Secretary Xavier Becerra was in second place with 25.6 percent, followed by Democratic financier Tom Steyer and Republican Sheriff Chad Bianco.

In California, the world's fourth-largest economy, the first- and second-place winners of the primary election advance to the gubernatorial election - regardless of party.