Watch: Rubbish truck workers surprise favourite customer with 100th birthday cake

Rubbish collectors have surprised their favourite customer after showing up to her door on collection day with a cake for her 100th birthday.

The group of men from the UK were filmed singing "Happy birthday" as they knocked on her door.

As she opened the door the men, who were wearing hi-vis jackets, told her to blow the candles out and make a wish, jokingly saying "to live to 105".

The woman they call Mercy was left with tears of joy at the men's gesture as they lit the candles.

Clearly taken aback by the gesture, the 100-year-old was speechless as she put her head in her hands while balancing on her walking stick.

The bin collectors had carefully walked up the garden path of their favourite customer with a pink birthday cake. Photo / Reddit

The 100-year-old woman known as Mercy wept tears of joy at the act of kindness from the bin collectors who surprised her with a birthday cake to celebrate her birthday. Photo / Reddit

The video was posted to social media, with many confessing the heartwarming gesture made them tear up.

"I'm not crying you're crying," one person wrote.

"I am crying," added another, as another said, "I'm at work and this almost made me shed a tear. Good lord this so precious."

Others praised the selfless act of the bin collectors: "Awesome bros! Wish more people would be like this. So many elderly people alone wanting nothing more than a little company and attention."

"This is honestly one of the nicest things I've ever seen.

"I used to work in a retirement home and there's nothing more special than seeing the residents be surprised and happy by nice gestures. We don't tend to think about it a lot, but old age can be very hard for a lot of people and I'd imagine this really helped brighten up her day."