WHITNEY HOUSTON FUNERAL BOBBY BROWN ALEADY LEFT

 Whitney Houston's funeral has only just begun ... but Bobby Brown has already left the church.

It is unclear if Bobby left on his own accord or if he was asked to leave.

Our camera guys outside the funeral spotted Bobby ever-so-briefly on his way in ... and his SUVs returned a short time later, though Bobby cannot be seen leaving (see video below).

Rev. Al Sharpton tweeted just moments ago, saying, "I am at Whitney's funeral. I spoke with Bobby Brown trying to calm him down and not distract from the services. Today is about Whitney!"

As TMZ first reported, after some opposition from some family members ... Bobby was officially invited to the funeral today.