Once Upon a Time star, sterne on Hook and Rumple's heartbreaking ending 

Warning: This story contains major spoilers from the series finale of

ended its seven-season run with one big happy ending, as the newly crowned Good Queen Regina cast a new curse that united all the realms as one. But not everyone lived to see the happily ever after.

As Wish Rumple (Robert Carlyle) enacted his final plan, portals began to open up that would suck each fairy tale character into their own isolated story. When Alice (Rose Reynolds) nearly got pulled into her portal, Wish Hook (Colin O’Donoghue) reached out to save her, his cursed heart be damned. With Hook near death, the real Rumple decided to sacrifice his own life by ripping out his heart and putting it in Hook’s body. The effect was two-fold: Wish Rumple disappeared and Hook was cured of the ailment that had long kept him separated from his daughter, Alice.

“When I found out that Rumple was going to give his heart to Hook to save him, or essentially allow him and Alice to be together, I remember thinking it was just such an amazing way for this relationship that Bobby and I have invested in over six seasons, that’s been so integral to both of our characters, to end,” O’Donoghue tells EW.

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Hook, who joined the show’s fairy tale ranks as Captain Hook in season 2, has had a long and storied history with Rumple. (tldr; Hook was going to run off with Rumple’s wife, so Rumple killed her and took Hook’s hand, leading Hook to hunt his “crocodile” for centuries.) Rumple’s sacrifice for Hook meant all the more to O’Donoghue because it showed how far these two characters had come.

“I thought it was a really beautiful moment and very, very important to me, as an actor, for them [to get this moment] and for that to be the happy ending for Hook,” O’Donoghue says. “Not to be some sort of magical thing, but for Rumplestiltskin to sacrifice everything to help, as he puts it, ‘my only friend,’ you know? I thought it was kind of heartbreaking.”

Read our postmortem with executive producers Adam Horowitz and Edward Kitsis here, find out how Lana Parrilla reacted to Regina’s ending here, and get the scoop on Alice and Robin’s unfinished story here.