Did Miley Cyrus and Liam Hemsworth finally tie the knot for real?!

We've all been speculating about the marital status of these two for years and now another clue in the mystery has popped up ... the couple's surfer pal Conrad Carr posted some telling videos to his Instagram Story -- including a shot of Liam and Miley holding a knife, preparing the cut the white cake in front of them!

Miley's wearing what appears to be a white, off-the-shoulder silk dress, Liam a tux and Miley's mom Tish is standing by. There's a fancy dessert table and the centerpiece is a simple white, two-layer cake with pink roses on a rustic wood stand.

The couple are celebrating the holiday ... and perhaps their marriage! ... in their Nashville home. Miley, 26, and Liam, 28, met on the set of the 2010 romantic drama The Last Song and the Aussie native proposed in May 2012. The two split in 2013 and got back together two years later.

Let's face it, these two are meant to be ... we hope they really took the plunge this time!

Check out what appear to be the groom and his best men taking shots off a wooden bar and Miley's sis Noah getting emotional!