Alyson Hannigan proposal

Alyson Hannigan, left, and Alexis Denisof celebrated their 10-year wedding anniversary with a proposal, new ring and upcoming vow renewal. (Richard Shotwell / Invision / Associated Press)

OK, Alyson Hannigan and Alexis Denisof. Just STOP IT.

The two overly cute "Buffy the Vampire Slayer" alum have made the hearts of their adoring fans melt just by showing off that they're adoring fans of each other.

"My hubby @AlexisDenisof surprised me with the most romantic day of my life yesterday! Which included another proposal & ring! I said YES!" the 39-year-old "How I Met Your Mother" star tweeted Sunday.

STOP IT, right?

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Denisof, 47, who has played sleazy anchor Sandy Rivers on Hannigan's "HIMYM," celebrated their 10th wedding anniversary by re-proposing, giving the mother of his two daughters -- Satyana and Keeva -- the new sparkler and promising a vow renewal.

"And now we get to have our kids at this ceremony :) It'll be shorter. We'll get to the cake sooner! YAY renewal!!!" she tweeted.

Hannigan stepped out Tuesday more than ready to show off her new bling -- a giant solitaire -- to photographers as she smiled and held up her hand for the quintessential "I'm engaged, check out my ring" photo.

Hannigan met Denisof on the set of cult fave "Buffy" and they married in 2003.

The actress will return this fall with castmembers Josh Radnor, Neil Patrick Harris, Cobie Smulders and Jason Segel for the ninth and final season of their CBS romantic comedy (and finally reveal more about the titular mother's identity).

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