The Big Bang Theory's Kaley Cuoco announces her engagement to boyfriend Karl Cook

The Big Bang Theory star Kaley Cuoco has announced her engagement to boyfriend Karl Cook in an emotional video.

The actress, 32, and professional equestrian Karl, 26, confirmed the happy news by sharing a short clip to his Instagram account, showing Kaley sobbing with happiness almost immediately after the moment took place.

'Honey? How do you feel, honey? What's on your finger, honey?' Karl is heard asking his new fiancée from behind the camera.

'We're engaged!' a visibly emotional Kaley exclaims, although Karl is quick to quip back: 'You still haven't said "yes" yet.'

'Yes! I say yes! I say yes!' she replies enthusiastically.

In the caption alongside the sweet film, Karl wrote: 'Well after nearly two years I finally got up the courage to ask her to marry me.'

'This is the best night of my life and I think the video shows it is the best night for kaley as well.....of she said yes!!!!!'

He also shared an image of the stunning diamond ring he'd used to pop the question to Kaley, adding: 'I am so so so happy. Thank you @nadis_diamonds for making the greatest ring I could hope for. Absolutely brilliant. Thank you thank you.'

Fans have rushed to congratulate the evidently very happy couple on their news, with one writing: 'Omg legit crying here 😢😭 so happy for you both congratulations 🎉.'

'You two are so adorable 😍,' said another. 'Love your relationship 😊 You two are goals! Always stay like this! I wish you a lot of love and happiness all the time!'

The wedding will be the second marriage for Kaley, who finalised her divorce from her first husband, tennis player Ryan Sweeting, last May.

'Kaley Cuoco and Ryan Sweeting have mutually decided to end their marriage,' a representative for the couple stated at the time.