Billie Eilish really made this teacher’s summer.

Earlier this summer, British singing teacher Sheridan Coldstream posted a video of himself on TikTok playing a piano rendition of Eilish’s song “Listen Before I Go”.

READ MORE: Billie Eilish Dances Up A Storm To Her Own Song At Dodgers Game In L.A.

Coldstream urged followers to sing along; he got a big surprise when last month, Eilish herself recorded a TikTok Duet of herself doing just that.

@billieeilish

#duet with @sheridan_coldstream

♬ original sound – Sheridan

 

“This is the greatest possible compliment I could ever receive!! I couldn’t be more touched and flattered ❤️I adore this song and you! Thank you 🥰,” Coldstream commented at the time.

In the time since, the clip has amassed over 32 million views and 6.5 million likes on the platform.

Speaking to BBC News, Coldstream said the video was “completely astounding,” noting that she even followed some of his singing instructions.

“There’s a bit in the song where she normally goes down,” he said. “I suggested that some singers may want to take it higher and she did exactly that, so I was gobsmacked.”

He added, “It was immensely exciting and I found the whole thing very moving, it made me tear up several times.”

READ MORE: Billie Eilish Surprises Fans In Hollywood With Short Set To Celebrate ‘Happier Than Ever’ Anniversary

Coldstream also talked about getting on TikTok in May after one of his singing students suggested it.

“It’s a completely different world to anything I’ve ever done,” he said. “It is completely mind-blowing and the reaction has been fantastic.”