The musical wedding episode, "The Song in Your Heart," airs Sunday, May 7.

After the April 23 episode, ABC shared a brief promo for the musical wedding hour, after airing the promo for next week's April 30 episode, "The Black Fairy":

TVLine got the first look at Hook's velvet wedding attire:

Jennifer Morrison (Emma) shared more on the inspiration for her character's wedding dress:

Day 101: Emma's wedding gown! So much love and thought went into this dress. Just as #onceuponatime pulls from fairytales and literature - for the wedding, Eddy, Adam, Edwardo, and I felt it would be wonderful to pull from the real life fairytale of Grace Kelly. It is a dress that represents the elegance and simplicity of classic timeless strength mixed with the delicacy of feminity and vulnerability. It is the ultimate balance that Emma has been fighting for throughout the 6 seasons. A wholeness. A balance. Not all one thing or another - But rather, a moment that is genuinely, truly, authentically her without barriers and walls. A woman surrounded by people she loves and is loved by, willing to fight to protect them all as well as herself. The joy of a timeless balance. So honored to wear such a beautiful gown. Eduardo and his team created a piece of art once again. The perfect way to end this round of #101smiles #emmaswan #wedding #uglyducklings

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Stunning. "Once Upon a Time" airs Sundays at 8 p.m. on ABC.

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