Harry, who turns 30 on Monday, had invited close friends to a mini banquet last night at Kate and Prince William's newly refurbished apartment in Kensington Palace.
Last week, he contacted his guests and announced he felt it was "inappropriate" to carry on with the party in light of Kate's illness, The Mirror reported.

"Harry was in no doubt that the party should be postponed, even though 30 is an important milestone," a source was quoted as saying.
Camilla Thurlow, 25, rumoured to be Harry's new girlfriend, is thought to have been among the disappointed guests, along with best friend Guy Pelly and cousins Beatrice, Eugenie and Zara.
Kensington Palace officials confirmed last week that Kate had been suffering from morning sickness after becoming pregnant for a second time.
The source said: "Kate had been very involved in organising Harry's party, and once she fell ill he felt it wrong to let the event go ahead."
Kate's sickness, known as hyperemesis gravidarum, led to her being hospitalised when she was pregnant with Prince George.
Sources said Kate, 32, was yet to reach the 12-week stage, but her sickness led to the pregnancy being announced earlier than planned.
Harry, who will tomorrow inherit 10 million pounds left to him by his mother Princess Diana, spent the weekend watching the Invictus Games.
He is expected to fly off for a short break this week.

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