Once-in-a-lifetime opportunities are just that, and two young Australian anglers had theirs last week — a friendly, close encounter with a southern right whale.

The teenagers were returning from a fishing trip when they saw the whale in Sydney Harbor.

The teens told local newspapers that the whale appeared to be asking for help as it swam close to their boat. Watch as one of them removed fishing lines and rubbish bags from its mouth.

https://www.youtube.com/watch?v=jxvl3ykpUFk

“It was surreal. We couldn’t believe our eyes,” Ivan Iskenderian, who removed the trash from the whale’s mouth, told The Daily Telegraph.

Afterward, Iskenderian said, the whale appeared to show its appreciation by slapping its fin on the water.

His buddy, 17-year-old Michael Riggio, even took a selfie with the whale.

Once in a lifetime.