Crystal Harris found it hard to buy her husband Hugh Hefner a birthday gift.

Although the bash was a huge success with over 50 guests in attendance, Crystal had a hard time getting a present for Hef because he wears the same clothes everyday and owns almost everything you could ever want.

Speaking to US TV channel KTLA, Crystal said: "He wears the same kind of thing, his pyjamas, every day. [He owns] maybe 200 [pairs] in every colour imaginable. He eats the same kind of food, he wears the same kind of cologne ... It's very hard to get him something."

After using her imagination, Crystal came up with a unique gift for her hubby - a 3D artwork which features several of his favourite things.

She revealed: "It's a collection of Playboy magazines and recycled items ... sunglasses, pipe, tobacco he used to have in a little container, even Altoids (mints). His favourite ice cream is strawberry Häagen-Dazs. There's a little container of that on there somewhere."

The couple got married in December last year several months after the Playboy Playmate called off their original wedding.

Despite facing criticism because of their 61-year age gap, Crystal insists she is blissfully happy with Hef because he is so romantic.

She revealed: "I'm having the time of my life. He's an amazing man, such a romantic. For Valentine's Day, he was like, 'What kind of flowers do you like? Do you like roses? Do you like mixed flowers?' I like everything, so he got me everything ... He's just so sweet."