Robert Irwin had everyone talking about his 'DWTS' chemistry with Xochitl Gomez ... everyone except the Aussie himself, who just sidestepped the romance questions like a pro!

We grabbed Robert as he rolled into practice Wednesday in L.A. ... and when we asked if he and Xochitl are a thing, he swerved hard, launching into a lil’ monologue about how they had the best time and how their two dances were so much fun. Cute answer ... but not the answer.

TBH, his non-answer doesn’t shut down the rumors at all -- 'cause if there was nothing going on, he could’ve just flat-out denied it. Instead, he left the door cracked wide open, which is exactly how a showmance is born ...

It wouldn’t exactly be a shock, either ... fans were already shipping the 21-year-old conservationist and former champ Xochitl after their jive in the Dance Relay, where six past Mirrorball winners returned.

But for now, Robert’s clearly locked in on keeping that momentum rolling ... after all, he’s the season’s hot favorite, and he’s not about to let a little romance buzz trip up his Mirrorball mission!