We got Mauricio leaving his "Dancing With the Stars" rehearsal Thursday in L.A., and our photog asked if he's got a good relationship with Morgan.

Mauricio says he's a big fan of Morgan, and he's inviting her to one of his 'DWTS' tapings. Hell, we might've given the show's producers a great idea, too, when we asked him and his pro partner Emma Slater about possibly dancing to one of Morgan's songs.

Spoiler: They're open to it!

His reaction to the Morgan topic is super interesting -- remember, he and Kyle recently separated after 27 years of marriage, and there's been endless speculation Kyle and Morgan are an item.

For their part, Kyle and Morgan have had fun with the buzz. They filmed a music video, and this week they've been touring Paris, the City of Love, together.

By all accounts, Mauricio and Kyle have kept things very amicable since the separation ... they've been co-parenting their 4 kids and even took a family trip together to Positano.

MU seems genuinely happy and jovial in our clip -- and, if it's all an act, someone should hand him an Oscar ... because he doesn't seem threatened by Morgan at all.