You literally never know what will happen on a TMZ Brunch Bus tour! While "FBoy Island" star CJ Franco was hosting, "Love on the Spectrum" star Abbey Romeo boarded the bus ... as a passenger!

That's right ... Abbey may be a breakout favorite from one of Netflix's premier shows, but she wanted to get a tour of Hollywood just like any other tourist while she was in town.

But she didn't take a backseat for long.

Check out the video ... We convinced the Disney fanatic to hijack the mic for a song. The incredible DJ Blue -- who was spinning records all afternoon -- picked an extra special number for Abbey, playing the Hannah Montana song "The Best of Both Worlds" for her to belt out alongside CJ.

And Abbey's mom, Christine Romeo, got in on the fun, too. She showed us why the party's on the westside, dancing to Montell Jordan's "This Is How We Do It."

Not to be outdone, CJ was an absolutely stellar host, bringing along her own hype crew!

Watch the video to see how CJ reacted to The Butcher, The Baker, The Cappuccino Maker serving her a specialty "FBoy Island"-themed drink.

Grab your tickets for the next bus here!