The Beatles' legend has invited Heather to the intimate celebrations at his
Peasmarsh estate next Monday (18.06.07).
A source told Britain's Sunday Mirror newspaper: "We are talking about a
total and very quick transformation from a state of complete vitriol between
the two of them to something much more amicable.
"Before she went to America, they wouldn't speak on the phone, now they can
have a civil conversation.
"It's as though Paul has chosen saturation point with all the bitterness and
Heather - aware of the battering her public image has taken - has decided to
genuinely try to bury the hatchet.
"Paul has had enough of all the spite. The divorce has effectively been
placed on hold."
Heather - who has been embroiled in a bitter divorce battle with Paul since
they split in May 2006 - is set to present Paul with a vegan birthday cake
at the party.
Two weeks ago, Heather, 39, and Paul were seen meeting in a North London
restaurant, sparking rumours they had decided to end their feud for the sake
of their three-year-old daughter Beatrice.
Relations between them have improved so much friends claim they have been
meeting regularly and that Paul even sends Heather "little notes and
flowers".
Last week, Paul wowed a select group of fans at a secret London concert.
The star, who performed for just 1,000 people, debuted tracks from his
eagerly anticipated new album, 'Memory Almost Full' and delighted the crowd
with a series of Beatles classics, including 'Hey Jude', 'Get Back' and
'Back In The USSR'.