"We look like a terrible, tragic joke," he said in WhatsApp messages to Dominic Cummings and Lee Cain.
The latest addition will be the couple's third child.
The outgoing prime minister's supporters were rewarded for their loyalty with invitations to the big-money bash.
James Cleverly: "It’s churlish to be negative about two people who want to celebrate their marriage and their love for each other.”
The couple were said to have sent save-the-date cards to family and friends for the celebration on July 30.
The paper had claimed Boris Johnson had wanted to give his then-girlfriend a top Foreign Office job.
Social media reacts as the under pressure PM gets a taste of public anger.
The prime minister's wife could be summoned to give evidence to MPs over fresh partygate claims.
"If you can’t trust the prime minister to make sure the rules he made were followed, what can you trust him to do?”
Why new pictures of the PM raising a glass at a leaving drinks during lockdown raise questions about knowingly misleading parliament.