Kevin Garnett Squashes Beef With Ray Allen At Jersey Retirement Ceremony

One of the biggest beefs in NBA history has officially been squashed -- Kevin Garnett extended an olive branch to Ray Allen at his jersey retirement ceremony on Sunday ... and it was beautiful.

Of course, there was bad blood between the two Celtics champions ever since Allen left Boston to join the Miami Heat in 2012 ... breaking up the big three of KG, Allen and Paul Pierce after one title.

Tensions still appeared be high between KG and Allen during this past All-Star Weekend ... when Garnett hit his ex-teammate with a piercing stare during the 75th anniversary team ceremony.

But, all the hatred is a thing of the past -- as Allen was in attendance at KG's retirement ceremony ... with the two embracing at center court in the middle of the Big Ticket's speech.

"It's good to see Ray Allen here," Garnett said during the special moment. "Real s***. It's good to see you, man."

Allen then approached KG and gave him a hug ... with Pierce joining in for the touching moment.

KG says Allen should be the next Celtic to have his number in the rafters ... making him the final member of the big three to receive the honor.