You're the best thing....

I'm been searching the net like crazy but i just can't seem to find the song I'm looking for. I have no idea who sings it, but i think it's a woman.And it might be a mid or late 80s song... not sure there either... but the lyrics go something like this:

You're the best thing that ever happened to me. You're that once in a lifetime thing. No words can describe it....

PLEASE! Can anyone help me? Who sings it? The name of the song?

Thanks
Mrs L

Are you thinking of "Best Thing That Ever Happened To Me" by Gladys Knight?

It's not the song I'm looking for, but thanks anyway