The EDM star was lost for words when the 'Man! I Feel Like a Woman' hitmaker interrupted his interview on the red carpet ahead of the event and didn't think his night could get any better.
As he held hands with Shania, the producer told 'Entertainment Tonight': ''This is amazing! I'm starstruck right now. I don't know what to say, I mean, it's Shania Twain!
''This is amazing. I can't believe this happened.
''I thought I was gonna be early and no one was going to be here, and then I saw you and I'm like, 'I'm gonna go home now.''
And when it was suggested that Diplo - whose real name is Thomas Wesley Pentz - should remix Shania's biggest hit, her 1998 single 'That Don't Impress Me Much', the 54-year-old singer was delighted to hear he'd already made one.
He said: ''I play it every night, I have a remix of that already. I gotta send it to you.''
Shania excitedly exclaimed: ''You do? I wanna hear it!''
The 41-year-old producer - who has previously worked with the likes of Gwen Stefani, Beyonce, Madonna, User, Justin Bieber, Snoop Dogg and Britney Spears - was hopeful their meeting could lead to a future collaboration too.
He quipped: ''Then we're gonna do something new, too.''
Meanwhile Shania closed the ceremony with a mixture of her classic tracks and covers of contemporary hits in what was her first AMAs appearance since 2003.
She began with a stripped-down acoustic rendition of snippets from Post Malone's 'Rockstar', Twenty One Pilots' 'Stressed Out', Taylor Swift's 'Shake It Off', Drake's 'God's Plan' and her own 'You're Still the One' before the performance ramped up and, as she was joined on a glowing staircase by a group of topless cowboy dancers, she moved on to her own songs, 'Any Man of Mine', 'That Don't Impress Me Much' and 'Man! I Feel Like a Woman!'.
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