Atlanta-based rapper Lil Nas X had an unexpected hit with “Old Town Road” — a sub-two minute rap song that gained widespread popularity on social media platforms. Perhaps even more unexpected was the subsequent remix of the track featuring a verse from “Achy Breaky Heart” by country singer Billy Ray Cyrus, the man behind one of the most popular country albums of all time.

It wasn’t long before the single reached No. 1 on the Billboard Hot 100.

Popular music has a history of unexpected bedfellows. Musicians often team up to reach potentially new fans, especially if the artist they’re partnering with works in a different genre. They may also simply be a fan of one another’s work and desire the opportunity to collaborate on a creative process.

Some of the world’s most famous musicians — including Michael Jackson, Taylor Swift, and Elton John — have taken part in unexpected musical alliances. Frequently, it’s to record a single track, but sometimes artists ultimately produce an entire album of work together. With all of the talent involved, it’s no surprise that many of these collaborations were highly successful, obtaining critical and commercial success. Some, however, were less fortunate.

Click here to see 25 of the most bizarre musical collaborations.