Taylor Swift was so miserable with one of her ex-boyfriends she would "hunch over" every time she talked about him, according to her pal Todrick Hall.

The Shake It Off star has been in a relationship with British actor Joe Alwyn for almost a year following romances with Scottish DJ Calvin Harris and Thor star Tom Hiddleston.

According to her singer pal Todrick, Taylor wasn't herself when she was with one of those past exes, and she would hunch over when she spoke about them, leading Todrick to dub her Quasimodo, the fictional character also known as The Hunchback of Notre-Dame.

"There was a time last year - I don't know if I'm supposed to say anything - she was dating someone," he said on The Kidd Kraddick Morning Show. "I'd actually never met this person, but I could, I could just tell every time I would talk to her, she would hunch over.

"I sent her this picture of her as Quasimodo that I edited... Because I was like, ‘You cannot turn into Quasimodo for this guy. Every time you say his name, you hunch over.'"

Todrick didn't name the ex, but many fans have guessed he was talking about Tom, as the English actor split from Taylor in September 2016 after a short-lived romance. It’s also thought Todrick met Calvin.

But Todrick thinks Taylor has now found her perfect match with Joe.

“(She’s the) happiest I've ever seen her", he smiled. “She's so happy. Standing up completely straight and so tall and so confident. I just love it. I'm so, so happy for her and I cannot wait to see this tour."

During the radio interview, the former American Idol contestant also revealed the 28-year-old was very sensitive to criticism.

"I think it's that passion and that humble quality about her that makes her so great at writing songs that people identify with because she wears her heart on her sleeve. When things happen, it really, really gets to her," he said.