The Carrie Underwood-Guns N' Roses connection continued this week in Los Angeles. Axl Rose made a surprise appearance during Underwood's show at Crypto.com Arena, performing the GN'R classic "Welcome To The Jungle". It's not the first time the two singers have teamed up - Last year, they performed "Sweet Child O' Mine" and "Paradise City" at an Underwood show in California and a Guns N' Roses show in London. Underwood has often cited Axl as one of her biggest influences as a singer. What's the most surprising guest star you've seen at a live concert?