The 'Girls Trip' actress was presenting the Best Hip Hop award with Kevin Hart and couldn't resist mocking the band, who went their separate ways in May, while praising their former member Camila Cabello.
After initially struggling to pronounce the 'Havana' hitmaker's name, Tiffany said: ''She's nominated for five VMAs tonight, five of them.
''I'm super proud of her. So those of you watching at home, hi Fifth Harmony.''
Kevin and Tiffany then announced Nicki Minaj won the Best Hip Hop prize and when the 'Chun-Li' singer took to the stage at Radio City Music Hall in New York to accept her Moon Person, she jumped to the defence of Fifth Harmony's Normani Kordei.
She said: ''Tiff, don't be coming for Fifth Harmony, because Normani is that b***h.''
Camilla, 21, took home the two biggest prizes at the event, Artist of the Year and Video of the Year for 'Havana', and dedicated the latter to Madonna, who had handed her the award.
She said: ''My hands are literally shaking. I am never going to forget this moment ever in my life. Madonna, I love you so so much, I've seen every single music video of yours, I've seen every single documentary of yours, you've inspired me so much. For that reason, this is a surreal moment and I love you, seriously. I can't believe it.
''Video of the Year, wow. Thank you so much all of my fans for voting.
I want to thank Dave Myers for being an incredible director and collaborator, and for putting up with me blowing up his phone every time we make a music video.
''I wanna thank the amazing choreographers on this music video, I wanna thank all the amazing actors in the video, I wanna thank my family who inspired this music video, I wanna thank my fans again, and honestly I dedicate this to Madonna. Thank you!''
His new album Underneath It All is out now.