Supergirl Dons a Wedding Dress in Mr. & Mrs. Mxyzptlk Photos

In the final moments of Monday's "Luthors" episode, Supergirl finally admitted to Mon-El that she has romantic feelings for the handsome Daxamite. As she's leaning in to seal their new relationship with a kiss, fifth-dimensional prankster Mr. Mxyzptlk appears, spoils the sweet moment, and declares his love for her.

Click on our gallery, to see preview images for next Monday's "Mr. & Mrs. Mxyzptlk" episode. They feature Kara Zor-El in a tasteful, strapless wedding dress being wooed by Mr. Mxyzptlk, Alex and Maggie having a very special Valentine's Day date, and nerdy Winn out on a date.

When Mr. Mxyzptlk (guest star Peter Gadiot), a magical imp, shows up on Earth and declares his love for Kara (Melissa Benoist), she tries to let him down easy, thinking him harmless. However, he decides it's a challenge and starts to wreak havoc on National City. Mon-El (Chris Wood) has seen beings like Mr. Mxyzptlk on Daxam and knows how dangerous they can be. He and Kara argue over how to get rid of Mr. Mxyzptlk, further straining their relationship.

Meanwhile, Alex (Chyler Leigh) and Maggie (Floriana Lima) celebrate their first Valentine's Day together.

Stefan Pleszczynski directed the episode written by Jessica Queller & Sterling Gates.

MORE: Supergirl: First Look at Mr. Mxyzptlk! / Supergirl Recap with Spoilers - Luthors / Lena Luthor's Secret Origin Revealed / Supergirl: First Look at Young Lex Luthor

Distributed worldwide by Warner Bros. International Television Distribution, SUPERGIRL is executive produced by Greg Berlanti (Arrow, The Flash), Ali Adler (The New Normal), Andrew Kreisberg (The Flash, Arrow) and Sarah Schechter (Blindspot, The Mysteries of Laura). Supergirl is based on the characters created by Jerry Siegel and Joe Shuster and appearing in DC Comics, by special arrangement with the Jerry Siegel Family.

"Mr. and Mrs. Mxyzptlk" episode of Supergirl airs Monday, February 20 at 8 p.m. ET/PT.