Rob Gronkowski's GF Camille Kostek Rocks Tiny Bikini In SI Fashion Show

Camille Kostek is becoming a bikini force to be reckoned with ... Rob Gronkowski's GF hit the runway at Miami Swim Week in a super small bikini -- and the pics are awesome!!

Kostek and Haley Kalil were 2018 Sports Illustrated Swimsuit Edition rookies -- and they hit Swim Week to coach the next batch of bikini models during the Sunday night show at the W South Beach.

Tons of women showed up for the casting call -- but show producers only selected 16 girls to walk the runway ... and, judging by the pics, they chose well.

As for Kostek, she was also hanging behind the scenes with Olivia Culpo -- who's dating Danny Amendola ... Gronk's former New England Patriots teammate.

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