'Wicked' Jonathan Bailey Signs Pic From 'Fellow Travelers' Toe-Sucking Scene

Worlds are colliding for Jonathan Bailey ... he's starring in the new "Wicked" movie with Ariana Grande, but fans won't let him forget his toe-sucking scene in a hit TV series.

Here's the deal ... Jonathan was at Monday's "Wicked" premiere in Mexico City when some folks in the crowd got his attention ... with a printed-out photo of his infamous "Fellow Travelers" scene where he sucks costar Matt Bomer's toes.

Footage from the funny exchange shows Jonathan walking past a group of fans before stopping in his tracks when he notices someone holding up the toe-sucking print. His eyes light up and he happily autographs the photo, then poses for a pic.

Of course, "Fellow Travelers" tells the story of 2 men engaging in a decades-long romance in Washington, D.C. back in the day, and there's a lot of provocative sex scenes ... with the toe-sucking moment standing out.

Matt's on the record saying he and Jonathan are forever bonded together as a result ... and we're seeing that play out here.

Jonathan's playing Fiyero Tiggular in "Wicked" ... but it seems his toe-sucking skills are still his claim to fame.