The 51-year-old pop star teamed up with the iconic rapper for a rendition of their hit tack 'BURNITUP!', from her LP 'Unbreakable', as she brought her run to an end in Atlanta, Georgia over the weekend.
The 'Sock It To Me' star was delighted to join Janet for the special performance for fans.
Taking to Twitter, the 46-year-old musician tweeted: ''We been friends for two decades & I'm still AMAZED EVERYTIME you PERFORM!
''You are ICONIC/LEGENDARY & even with all your accolades you have every right to feel yaself but u are so HUMBLE! I couldn't ask for a better friend/sis. (sic)''
Meanwhile, Busta Rhymes recently heaped praise on Janet, saying her voice is a ''God-sent talent''.
The hip-hop star has been friends with the singer - the younger sibling of the late King of Pop Michael Jackson - for decades, but he only got the chance to see his close pal live for the first time when he attended her show last month.
And Busta - who worked with Janet on the 1998 hit, 'What's It Gonna Be?!' - was blown away by the singer's show, and said he had now developed a ''fan obsession'' with the star.
Speaking after the concert, he said: ''I am losing my Janet Jackson live concert virginity tonight. There's a new fan obsession that has transpired for me.
''Me being an artist myself, I'm super-inspired in a whole new way. She is probably the most incredible, timeless, God-sent talent that I've ever seen in my life - I salute you queen!''
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