Kaley Cuoco
Kaley Cuoco stars as Penny in CBS' The Big Bang Theory Getty

After sweet reunions come double rainbows! At least that's the case for The Big Bang Theory star Kaley Cuoco, who took to Instagram to announce that she's "love struck" and "weak in the knees" for her boyfriend Karl Cook.

The 31-year-old actress shared a super romantic moment as she passionately kissed her animal-loving boyfriend under a sky with two rainbows, melting hearts on social media. Alongside she simply wrote, "Love struck and weak in the knees," tagging Karl, who goes by the name of @mrtankcook on Instagram.

And like always, die-hard fans of the Penny actress were quick to notice the heartwarming romance unfolding in Kaley's real life, as they responded with gushing messages and compliments.

"Get married already!" one enthusiast exclaimed, echoing the feelings of several other fans touched by the glimpse of Kaley's private life. "Aww! Get a room you two!" gushed another admirer.

As Kaley's loyalists bombarded the sweet photo with admiring comments, it was turn for her 26-year-old boyfriend to reciprocate the feelings with another romantic gesture.

Interestingly, the equestrian seemed to carry on with the conversation started by his girl by posting a follow-up image of their moment on the rain-drenched streets.

"The only one weak in the knees is me. I mean I couldn't be happier in any way shape or form," he captioned the image, wherein the two seem to be goofing around with Karl adorably lifting the CBS star.

"Waiting for the announcement. Not gonna lie," one user commented referring to the couple's much-anticipated wedding.

While most people were thrilled to see the pair together, some expressed mixed emotions – even a tad bit jealous at seeing Karl smooch the fan-favourite Penny star. "That is one lucky guy," someone commented, while another added, "You lucky son of a b***h".

Kaley and her boyfriend were most recently spotted rafting in the Royal Gorge region on the Arkansas River; and the latest pic comes on the heels of this adventure trip – pictures of which flooded the actress' social media.

The couple has been dating for over a year after they met during a horse show in 2016.