Ace of Base WAS the two ladies. The guys were just the background music.
I had heard this story more than 10 years ago. It is not a big secret.
A sad thing I heard was that the lead singer (the blonde) was stalked or threatened by fans or something like that and she started to put herself in the background in later videos. It was just some thing I heard — not sure if it really happened or not.
Yeah, teh ladies later sued teh guys for using “Ace of Base” for their name, so some slight band name alteratiosn were seen.