Matt Rife is officially off the market -- TMZ can confirm he’s dating fitness model Mariah Morse!

It’s unclear how long the comedian and the blonde bombshell have been an item, but one thing’s for sure -- they’re all in, with Mariah even posting a pic with Matt’s dog, Hammer, on Sunday.

It was a fun weekend for Matt and Mariah -- they were spotted holding hands as they entered a Rhode Island club, and she was also spotted by his side in a group IG pic.

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The pair haven’t spoken about each other publicly yet, but at this rate, it seems like it's only a matter of time before they go Instagram official.

Definitely looks like Matt has a type -- blondes! His last relationship was with actress and dancer Jessica Lord, but they called it quits last summer.

We reached out to a rep for Matt ... so far, no word back.