Janet Jackson -- No, I'm Not Engaged ... I'M MARRIED!

Janet Jackson is putting those pesky engagement rumors to bed ... by announcing she secretly got married to her mega-millionaire boyfriend LAST YEAR.

Janet and new hubby Wissam Al Mana -- a Qatari businessman -- released a joint statement today, claiming, "The rumours regarding an extravagant wedding are simply not true. Last year we were married in a quiet, private, and beautiful ceremony."

As for wedding gifts, the two decided NOT to lavish each other with expensive presents ... “Our wedding gifts to one another were contributions to our respective favourite children’s charities."