Shania Twain Says She Couldn't Ditch Harry Styles Concert For Taylor Swift's Wedding

Shania Twain says she wanted to see the culmination of Taylor Swift and Travis Kelce's love story in person ... but she'd already committed to T-Swift's ex, Harry Styles.

The country singer says she received an invite to the wedding of the century in an interview with the Canadian TV channel eTalk ... explaining she couldn't make it because she was scheduled to open for Harry at Wembley Stadium the same weekend.

It don't impress Shania much to simply drop out of a pre-planned show ... so she stayed across the pond and performed instead of packing into Madison Square Garden with the A-list crowd for the couple's nuptials.

Shania says she would've done almost anything to be at the ceremony ... but she's a woman of her word -- and it simply didn't work out with her schedule.

Adding to the drama is the fact Taylor and Harry dated back in the early 2010s ... though that all seems like water under the bridge now -- given Harry got an invite to the wedding as well. Heck, even Harry's fiancée Zoë Kravitz managed to attend.

Shania jokes that the whole situation has led to a new rule for Harry when it comes to his wedding ... if he wants her there, he'd better ask her way in advance.

Of course, we told you all about Taylor and Travis' wedding -- it's all anyone in Hollywood has been talking about recently ... and, even without Shania, the guest list was pretty dang impressive.