The 25-year-old actress found the late actor intimidating because he always insisted on staying in character as Professor Severus Snape.
Asked her fondest memory of Rickman - who tragically passed away after a battle with pancreatic cancer in January last year - Evanna exclusively told BANG Showbiz at the press launch for the addition of the Forbidden Forest at Warner Bros. Studio Tour London: ''Probably how much he scared me. I was really freaked out by him and he was always in character.''
However, she also remembers how he would always have lots of young children come and visit him on set.
She added: ''I think the best memory I have was going to the canteen and seeing him surrounded by all these little people. He always had all of his, I guess his friends' children with him.''
Meanwhile, Evanna - who played Luna Lovegood - has revealed she managed to keep some feathers from Professor Albus Dumbledore's (Richard Harris) phoenix companion Fawkes in the films and she had planned to turn them into earrings for one of the wizarding blockbuster franchise's premieres.
Asked if she ever stole anything from the set, she said: ''I didn't steal anything but I actually got feathers from Fawkes from Phoenix. I wanted to make earrings from them for my premiere dress.''
It comes after her co-star Jason Isaacs (Lucius Malfoy) revealed he couldn't swipe anything because Rickman pinched gold coins from Gringotts bank.
He recently recalled:''It was very difficult to steal things because Alan (Rickman) god love him, god rest his soul. He nicked all of the Gringotts coins on the very first day he did Goblins and swiped in and out like a supermarket. I couldn't get away with it.''
Jason - who portrayed Lucius Malfoy in the franchise - was also left embarrassed after a failed attempt to swipe a copy of wizarding newspaper The Daily Prophet.
He admitted: ''I once tried to take a copy of The Daily Prophet because there were thousands of them. I said I'd like one of those to director David Yates, who said, 'No problem mate'.
''I put it in my bag and when I got to the gates, they said, 'David said can he have it back'. It was so embarrassing. So I got nothing.''
The Forbidden Forest opens at Warner Bros. Studio Tour London - The Making of Harry Potter on 31 March 2017. Tickets are pre-book only and available at wbstudiotour.co.uk.
Once a fire fighter, always a fire fighter.
Today (September 14th) marks the 25th anniversary since the album's 1993 release.
Labrinth has teamed up with Sia and Diplo to form a new supergroup: LSD.
The Struts teamed up with Kesha for a red and gold themed music video as part of their collaboration on 'Body Talks'.
Sometimes actors are not acting.
Tanner and Brent Van Camp have been best friends for ages and both happen to...
Sharply important themes make this film a lot more important than its wacky style might...
The eight-part saga comes to a close with an action-packed finale that neatly ties up...
Harry Potter and his friends, Ron Weasley and Hermione Granger, continue their search for Voldemort's...
The final instalment of the Harry Potter series is almost upon us! Harry Potter and...
Watch the trailer for Harry Potter and the Half-Blood PrinceHarry, Ron and Hermione are fast...
It's gotten to the point where the quality of the films don't really matter: Now...