"Katy couldn't have looked happier. She was just beaming with a huge smile on her face. Katy, John and her parents ( mom Mary and dad Keith Hudson), seemed to be celebrating the night," showbizspy.com quoted a source as saying.
"They were laughing a lot and looked really at ease and comfortable with each other. They all looked relaxed, especially Katy and John. They were holding hands and when they weren't, John had his arm around Katy."
The couple has been dating since June 2012. They were initially reluctant to go public with their relationship, but that is not the case now.
Perry was earlier married to British comedian Russell Brand. They split in December 2011 after 14 months of marriage.
"Katy's parents also really like John. They prefer him over Russell. They thought Russell was too temperamental," said the source.