The 'Anything Could Happen' singer, who is dating McBusted's Dougie Poynter, played matchmaker between her two famous friends because she instinctively felt their pairing would be successful.
Speaking to the new issue of Cosmopolitan magazine, she said: "How did I set up Taylor and Calvin? It just kind of happened.
"They're both good people, both dear friends. I thought it might work, and it did."
Ellie and Taylor became friends after meeting on a talk show in 2012, and the British pop star admits she was worried about acting like a "t**t" in front of the 'Blank Space' superstar.
She recalled: "I was really nervous because she's such a legend and I remember thinking, 'Please don't act like a t**t, Ellie, don't say anything stupid.' "
Ellie relaxed when Taylor quoted one of her less well-known songs to her.
She added: "I thought, 'Wow, that's cool, Taylor is a badass.' "
Thank you @cosmopolitanuk for having me on the cover. @heleneimperiale https://t.co/yrTvIcTisQ
— Ellie Goulding (@elliegoulding) November 2, 2015
As well as Taylor, Ellie is also good friends with Adele and adores the 'Hello' singer's sense of humour.
She said: "We've been friends since MySpace days, she really makes me laugh.
"We talk about everything. Our lives, the world, the same things I talk about with my friends from school who do 'real' jobs."
Though she has a string of famous friends, the 'Burn' hitmaker is still great pals with the people she grew up with and she would love to be invited to a school reunion in the future.
She said: "High school and primary school are so special to me. If anyone said, 'We're having a reunion', I'd be so excited."