Band members (from left): Li Si, Dong Libing, Guo Beibei, Yang Songlin, Dong Bin and Tian Fangming. [Photo provided to China Daily]

On weekends, they fly to different cities, to perform at theaters and music festivals surrounded by cheering fans.

"It's quite relaxing to play music in your spare time, which increases my efficiency at work," says Dong, who also adds that the band members' jobs help them stay grounded.

Dong, a graduate from Beijing Forestry University, learned the piano as a child.

And she has known Guo Beibei, the lead vocalist; and Li Si, the bassist, for a long time - they were schoolmates of the same university.

In the autumn 2014, Dong asked Guo and Li to help her prepare for a performance at the Mid-Autumn Festival par-ty at Dong's institute.

The three schoolmates then teamed up, later attracting two colleagues of Dong to join in the performance.

After a year or so, the drummer Tian Fangming, was recruited by the band.

That's where Sir Deer's story begins.

Speaking about the band, Yang Songlin, 35, the rhythm guitarist, says: "All the songs are written, played and sung with sincerity from within.

"We are so happy to find that so many audience members get touched by our songs."

The band's 2015 debut song titled Chunfeng Shili (Spring Breezes Ten Miles), received more than 200,000 hits online and comments on the NetEase Cloud Music website and app.

The fans dote on the band so much that in 2016 they pitched in to help it produce its first album. Through crowdfunding, more than 7,000 netizens on Musikid.com raised a total of 300,000 yuan ($47,400) to cover the cost of the project.