They say never meet your heroes as it will end in disappointment. But for these starstruck celebs it was an awe-inspiring experience. Find out which stars, like Kim Petras when she saw Madonna, were left dumbfounded in the presence of their idols…

The ‘Black Widow’ actress couldn't believe her eyes when she spotted the 'Judge Judy' star at a restaurant. Scarlett said: "I couldn't believe it. "I was a little nervous. I mean, she's like an icon, obviously. I didn't know if she was gonna look at me and be like, 'Get away from my table, I'm here with my family,' and like, 'I'm Judge Judy, leave me alone!' But she wasn't like that. "She was wonderful. And I was so relieved that she was a very nice person. "She probably was, I think she was surprised that I was there, and I was very geeked out. I mean, I grew up with Judge Judy. She's amazing. She was very, very nice."

The ‘Harry Potter’ actress is used to fans fawning over her. But when Emma met Céline Dion at the ‘Beauty and the Beast’ premiere in 2017 she lost her cool. She said: "Céline Dion arrives and I'm like, holding my publicist like, 'This is almost too much for me!' "You have to understand, my parents do not really understand, like, celebrities or Hollywood or whatever else, but my mom and I used to play Céline Dion in the car, like, non-stop. Being able to tell her [my mother] that I met her I was like, 'She's gonna lose it. She's gonna know who Céline Dion is.'"

The ‘Happier Than Ever’ singer was over the moon when she met her love Justin Bieber for the first time at Coachella back in 2019. Billie previously admitted she was a huge fan girl and was moved by their encounter after Justin shared a snap of the pair and captioned it: "So, this happened… Long and bright future ahead for you." Billie later reflected on her meeting with the star, writing on her Instagram story: "Some of the most life changing things I'll ever experience happened over the weekend. And I don't want a bunch of pictures to have to prove that to anybody. Understand how moved I am. I don't know how to process and relay the love I feel for the people I feel it for. I feel full thank you."

Hemsworth's legs turned to jelly upon meeting his ‘Guardians of the Galaxy’ co-star Chris Pratt. He said: "The first time I really met Chris Pratt — and went on set with him and the Guardians — I was weirdly shaken. "I don't know why. He's just so charismatic. And good at what he does."

The ‘Unholy’ singer was high on life after meeting their pop idol Lizzo in 2019 whilst attending her show. Smith took to Instagram and gushed about the 'Good as Hell' hitmaker following the encounter. He said: "So truly happy I got to meet @lizzo the other day. "Truth Hurts "Her show was out of this world!! Made me feel so high on life!! She is the one. "Can't wait to watch you continue to take over the world gorgeous xx."

The Fleetwood Mac singer's 'dreams' came true when she met football legend David Beckham at her 2019 concert in San Francisco. She said: "He just oozed handsomeness. Gorgeousness, you know? "I just stood there, like, 'Is this real? Maybe it's a dream.' Anyway, he was super nice and really sweet."

The Oscar-winning star has been a huge fan of the Spice Girls since she was a teenager and got the chance to meet 'Baby Spice' Emma Bunton in 2019. Emma, who’s real name is actually Emily, previously revealed she asked to be called Emma because of her obsession with the popstar. She said: “My real name is Emily, but I wanted to be called Emma because of Baby Spice and guess what? Now I am. “It wasn’t necessarily because of her, but in second grade, did I go up to the teacher and ask her to call me Emma? Yes, I did. And was it because of Emma Lee Bunton from the Spice Girls? Yes, it was.”

The ‘Fantastic Beasts’ star and his wife Hannah Bagshawe were spellbound after meeting Jennifer Aniston at the Screen Actors Guild Awards in 2015. The ‘Friends’ fanatic revealed he was “incredibly inappropriate” when he met Jennifer, who played Rachel Green in the sitcom. He said: “We saw Jennifer Aniston at a party, and we were just incredibly inappropriate.” Redmayne admitted to keeping four metres behind the star for the entire evening in the hope of getting a photo.

Adele, another ‘Friends’ fanatic, was so starstruck when meeting Jennifer Aniston that she referred to her as “Rachel” when the actress asked her how she was.

The ‘Devil Wears Prada’ star lost her composure when she spotted Mariah Carey on the red carpet in 2015 at the premiere of 'The Intern'. She said: “She’s at my premiere, I mean it’s Bob’s [Robert DeNiro] movie premiere more than mine. "Oh my God. I’m freaking out. She’s two arm lengths away right now. “She’s now an arm length away. It’s fine, I’m going to meet here when the time is right. I just love that this is on camera right now."