Kendra Wilkinson didn't know how to mail a letter.

The former Playmate - who used to date Playboy founder Hugh Hefner - struggled to get used to life outside of his Playboy mansion, where she lived from 2004 to 2008.

Kendra, 23, admitted: "The first time I mailed something on my own, like a couple of months ago, I didn't put a stamp on it.

"My mom, said, 'Are you serious? You didn't put a stamp on your mail?' I'm like, 'Dude, I've never been on my own before, how am I supposed to know?'

"It was the biggest blonde moment of my life. It was a cheque too. I don't know where it went to."

Kendra - who rose to fame in the reality TV programme 'The Girls Next Door', which followed Hugh's girlfriends - left the mansion after splitting from the publishing magnate to plan her wedding to American football player Hank Baskett.

She will next star in her own reality show showing her adjusting to ordinary life. However, Kendra was reunited with her old boyfriend to celebrate his 83rd birthday with a pool party at the Las Vegas' Palms Resort and Casino on Saturday.

She attended the celebration with Holly Madison and Bridget Marquardt, who also left Hugh in 2008.

Hugh, who was also joined by his new partners Crystal Harris and twins Karissa Shannon and Kristina Shannon, said: "As you can tell I am very, very happy. To celebrate my birthday with new girlfriends and former girlfriends is perfect, it's wonderful."

Kendra brought Hank to the party with her, and admitted she'd like to pose for Playboy again if her fiance can take the pictures.

She said: "If Hank shoots the spread I will do it again. He has actually been practicing his photography skills."