Billie Eilish's TikTok duet leaves online tutor 'gobsmacked'

Billie Eilish's TIkTok duet with singing teacher Sheridan Coldstream has been viewed more than 30 million times

A singing teacher said he was "gobsmacked" when Billie Eilish duetted with his TikTok tutorial to her song.

Sheridan Coldstream, from Tingewick, Buckinghamshire, now has more than 163,000 followers on the platform.

Last month, the US singer-songwriter recorded herself singing her song Listen Before I Go alongside Mr Coldstream's piano accompaniment and instructions.

It has since had more than 32 million views and 6.5 million likes.

Mr Coldstream said he was being approached by businesses and TV production companies after the video's success

Mr Coldstream said it was "completely astounding" that not only was Eilish singing to his piano playing, but the 20-year-old was also following his directions.

"There's a bit in the song where she normally goes down," said the 58-year-old, who runs Total Vocal at his studio.

"I suggested that some singers may want to take it higher and she did exactly that, so I was gobsmacked.

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

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Mr Coldstream said he started posting on TikTok in May after a pupil of his suggested he get an account.

"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."

He said his followers ranged in age from teenagers to people in their 70s.

"People are discovering it is no longer this thing just for trendy teenagers," he said.