Few expected the couple to last this long, and even fewer expected what happened on social media on the day of their anniversary.
Not only did Brandi Glanville wish LeAnn well on the milestone occasion, but the ladies had a friendly back-and-forth like a couple of lifelong besties:
"@leannrimes Happy anniversary Happy 2 watch my boys 4 mybaby daddy so that y'all can celebrate! Get a tan for me #feeling pasty (mean it)," Brandi tweeted.
"@BrandiGlanville Thank you! Happy that we always pick up where the other leaves off. Xoxo," LeAnn replied.
"@leannrimes that's the point right?Thanks for taking care of my boys! Have fun," Brandi tweeted back.
It went on like that - and needless to say, we're more than a little surprised.
Brandi and LeAnn have been feuding for years, but it looks like they quietly buried the hatchet at some point in the past few weeks.
But the peace may have been short-lived.
Just one day after making nice with LeAnn on Twitter, Brandi posted this video on Instagram:
Needless to say, it's got a considerably more hostile tone.
Brandi raised even more eyebrows when she followed that up with this tweet:
"I just got my feelings hurt & realize that social media stalking is the root of all evil."
Hmmm...many fans interpreted the comment to mean that Brandi was stalking LeAnn and had her feelings hurt by something the singer said.
Tellingly, Brandi didn't respond to the fans who expressed those thoughts online.
Whatever the case, it seems that relations between Brandi and LeAnn are better than they were five years ago - but still far from perfect.