The Duchess of Cambridge wed Prince William in April before embarking on their honeymoon to the Seychelles.
On Thursday, the couple were guests of honour at Ark's 10th anniversary party to raise funds for deprived children. The charity auction raised £17.2m and marked the pair's first official engagement as a married couple.
"Kate said she was 'loving it' when asked what married life was like. She added that it was surreal sometimes but that's to be expected," a guest told The Mirror.
"She said she was totally and blissfully happy and her eyes lit up whenever William's name was mentioned. The pair are clearly so in love."
Acts performing at the party included Mark Ronson, Kings of Leon and divers in Speedos.
William joked: "I would like to share with you the conversation I am going to have with my grandmother tomorrow as I try and describe the swimming pool and the men wearing the most tight Speedos I have ever seen in my life."
It was recently revealed that Kate Middleton could have had her phone hacked by a private investigator.