Ellen Pompeo is reflecting on a 15-year-old beef on “Grey’s Anatomy”.

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Pompeo honoured her “Grey’s” co-star Kate Walsh on the 15th anniversary of Meredith and Addison’s first face-off. The show’s season one finale revealed that Meredith’s boyfriend, Derek, was married to Addison.

“Unreal that today marks 15 years to the day since this little lady walked on to your screen and checked ya for screwing her husband,” Walsh teased in a tweet.

“Thank God I messed with your hubby!!” Pompeo replied. “It worked out for us both… that scene when your character showed up was such a defining moment for [‘Grey’s’]. From that point on we had them hooked!!!”

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Season 16 of “Grey’s Anatomy” concluded on April 9.