Between the years of 1984-1985, musicians all over the world were reaching out to bring relief to the famine in Ethiopia. Bob Geldof, who some people in the States may know from his role as Pink in Pink Floyd's movie, The Wall, formed Band Aid, uniting musicians from the UK and creating the way too depressing "Do They Know It's Christmas?" Seeing the success of Band Aid, a couple of activists in the US got some musicians together to form USA for Africa, who sang "We Are the World," which was written by Michael Jackson and Lionel Ritchie.
Seeing the success of these two groups, the guys in Dio noticed something: All the musicians in those groups were strictly pop music. There was no support from the rock/heavy metal genres. So they got together their own group of musicians, Hear 'n Aid, and wrote a new song for the cause, "Stars."
Unfortunately, "Stars" did not become as successful as "Do They Know It's Christmas?" and was dwarfed by sales for "We Are the World," partially because contractual issues between the different artists' record labels delayed the release of the album almost a year after the fact. Still, it's a good song and a significant part of Dio history.
This song is actually interesting because it features a pretty long guitar solo done by nine different guitarists while the two guys in Iron Maiden lay down the rhythm guitars. In the video, you'll recognize quite a few people. Obviously, Dio is in there, but there's also guys from Blue Öyster Cult, Quiet Riot (including the late Kevin DuBrow), Rob Halford, Geoff Tate from Queensrÿche (I'm glad he got rid of that hairstyle), and, if you pay attention, you'll even see David St. Hubbins and Derek Smalls of Spın̈al Tap. That's a lot of extraneous umlauts.
Anyway, enough backstory. Just watch the video.