The 30-year-old, who hails from Termonfeckin in Co. Louth, starred as eccentric Hogwarts student Luna Lovegood in the Harry Potter series from the fifth film onwards.
Speaking on The Six O’Clock Show, Evanna said that she was a “huge fan” of Daniel Radcliffe, who rose to fame for his portrayal of Harry Potter himself, before she joined the cast.
“I still am [nervous talking to Daniel], I can't be normal around him,” she said.
“I try. He's very nice, he's very friendly. I think he's charismatic and he tries very hard to make people feel welcome.
“I just liked that he was quite an awkward person and quite a thinker, you know quite neurotic. I related with that.
“And I was like, ‘Oh there aren't many leading men like this.’ Maybe they are now but back in the day... Yeah, I was a huge fan.”
She was speaking after the recent 20th anniversary special and cast reunion aired on HBO and Sky on New Year’s Day, adding that she felt “privileged” to be invited back to the set despite the fact that she wasn’t part of the series from the beginning.
“It's strange I've been in the unusual position in the films in that I came in halfway,” she explained.
“So, when they were reminiscing about 20 years, for me it's 15 years. 20 years ago, I was just a fan watching them along with everyone else.
“So, to sort of be included as that core group, to be invited back to the reunion was very, very special.
“I felt really privileged. It's that thing, I tackle those feelings of unworthiness, ‘Why am I here, I don't deserve to be here.’
“But I had to just remind myself I've grown a lot and I've done a lot since and enjoy the moment more - probably more than I did when I was a teenager.”