"It's been an incredible byproduct of playing him. We have just become really quite close," Egerton, who portrayed John in the biopic Rocketman said on Tuesday.
The actor said that John gave him a drag name based on how he likes to take weekend trips with his girlfriend in an RV. John is known for giving friends drag names.
"The first part of my name is Blodwyn, which is a Welsh word meaning flower and my surname is Campervan. Blodwyn Campervan," he said of the drag name.
Egerton also mentioned how he gifted John a pair of glasses he wore during the filming of Rocketman, outfitting the frames with the musician's prescription lenses.
"He wears them when he's doing his crossword or I don't know, counting his jewels," Egerton joked.