JEFF PROBST is feud­ing with his wife’s ex – “Saved by the Bell” actor Mark-Paul Gosse­laar – because the “Survivor” host wants Mark-Paul’s bio­logical kids to call him “Dad”!

The two TV personalities have had a tough time seeing eye to eye since Jeff and his wife Lisa Ann Russell started hooking up while she was still married to Mark-Paul. And things have only gotten worse since Jeff and Lisa wed in December 2011.

“MARK-PAUL DIDN’T LIKE Jeff from the beginning,” said an insider. “He’s always looked at Jeff as a homewrecker.”

And Mark-Paul “really hates it” when Jeff talks about the kids – Michael, 9, and Ava, 6 – as if they were his own, adds another source.

In December, Jeff sat down with Larry King on Hulu’s “Larry King Now” to talk about his family and splitting custody with Mark-Paul, who’s now starring in the TNT legal drama “Franklin & Bash.”

When King commented that the kids don’t see Jeff as a stepdad, he responded by saying: “They’re not stepkids! They call me dad…when we got married, when this ring went on my finger, Michael looked up and said, ‘Dad,’ and I could tell that he knew now that this big thing was offi­cial and it was real.”

According to the in­sider: “That just made Mark-Paul crazy.”

Lisa and Jeff think Mark-Paul is acting jealous, but Mark-Paul feels as if he’s being pushed out of the picture, says the insider.

“He has been assured that will never happen,” the insider added.

“But Mark-Paul’s been telling pals if Jeff keeps up the ‘Dad’ talk, he’ll call him out face to face!”