This is despite her recording a duet with Elton John, "Act of war", which made it to 32 in the UK singles chart in 1985. Once again, maybe not the best choice for her to be taken seriously more widely ... it was a fun pop record that took advantage of her theatrics vocally and in the video, which was the whole point (I vaguely remember Tina Turner being asked first, rather like Dusty Springfield was first choice before Kiki Dee got "Don't go breaking my heart". Tina would have probably got more airplay.)
The following year Millie released a decent LP on Jive Records, "An imitation of love". That was an effort to be serious as it had none of the smutty stuff, but she was maybe let down a little by the production which is very much of its time. Some very good tracks on the album though.