A famous friendship for the ages! Kaitlyn Dever is opening up about what it was like sharing the screen with a pair of iconic Hollywood besties, George Clooney and Julia Roberts, in Ticket to Paradise.

Dever, 25, walked the red carpet at the premiere of her Shakespeare-inspired period comedy Rosaline in Los Angeles on Thursday, and she spoke with ET's Will Marfuggi about what it was like the first time she met Clooney and Roberts for their roles in Ticket to Paradise.

"I don't know, because I probably blacked out," Dever joked. "Just [meeting] one of them is a lot, and the two of them is an overwhelming feeling.

"I admire them so much, and I will say they are everything you want them to be and more!" she marveled. "I truly just love them so much."

According to Dever, one of the best things about working with them is getting to see their off-screen bond, up close.

"Their friendship is something that is so sweet," Dever marveled. "They love making each other laugh and it's the best thing to be around."

Dever stars opposite Clooney and Roberts in Ticket to Paradise, which hits theaters Oct. 21.

Meanwhile, however, fans will get a chance to see Dever take on a reimagining of Romeo and Juliet in her new comedy Rosaline -- which tells the famous story of the star-crossed lovers from the point of view of Romeo's jilted ex, Rosaline.

"I mean, the costumes were amazing!" Dever said when reflecting on her memories of shooting the project and the sizable, period-appropriate attire the film required. "Our costume designer, Mitchell Travers, designed the most specific and unique costumes! But yes, it was like I was walking around in a floor rug all day. And in the Italian summer!"

For Dever, getting to do a project based on the world of a Shakespeare play was exciting and very different, and she loved "the incredible dialogue" that filled the script.

"So many things were exciting, but I think mainly the dialogue and sort of being in a period film and being in a period era, but using comedic dialogue and modernized dialogue, it's really fun," Dever shared gleefully.