Pamela Anderson Joins Madonna Onstage at Vancouver Concert

Madonna brought out a special guest for her concert north of the border, playing to the crowd with a fan favorite and national treasure ... none other than Pamela Anderson!!!

Madonna was performing in front of a sold-out crowd Wednesday night at Rogers Arena in Vancouver -- when Pamela, the hometown hero, joined her onstage.

The two icons hugged and kissed on the cheek before sitting down together for Madonna's hit song, "Vogue." TMZ has it all on video ... Pamela and Madonna act as judges as models turn the stage into a runway, strutting their stuff and striking a pose in front of them.

As you can see, Pamela and Madonna are holding up scorecards as they judge the fake pageant on stage ... and it's mostly 10s across the board.

Madonna's obviously in full hair and makeup for her "Celebration" tour, but Pamela was fresh-faced and au naturel ... hey, no complaints here!!! BTW, this all-natural look is actually something Pam has been rockin' a lot lately -- it's kind of her new thing, in fact.

She's got a new skincare line out called Sonsie ... and the whole idea here about her products is that it's all about promoting minimalist beauty -- something PA is sticking to out in public. She's not wearing any makeup these days ... even when she's next to Madge!