You wouldn’t be the first person to tell Debra Messing that she looks like Lucille Ball. You also wouldn’t be the most important person to mention it — that honor belongs to Ball’s daughter, Lucie Arnaz.

Last year, the cast of “Will & Grace” filmed a very special “I Love Lucy” tribute episode, which aired on Thursday night. Messing recalled, on the “Variety After-Show,” the moment when Arnaz came into the dressing room to see her full transformation for the first time.

“I was in the green dress. We were about to shoot the song and dance [number] and she walked in and she just looked at me and didn’t say anything.” Messing told Variety. “Then she hugged me and she said, ‘This feels really good. It’s been a long time since I’ve hugged you,’ and everyone started to cry.”

“And then she smiled and she said, ‘I know how long you’ve been wanting to do this, Debra. And I’m so glad we were able to make it happen.’” And then I had to go [to the stage],” she continued. “As I walked away, she said, ‘Break a leg, Mom.’ Everybody just flipped out and cried. It was really moving.”

It was an emotional episode for Messing, who is a lifelong fan of Ball’s work and “I Love Lucy,” and described the opportunity to play her as a bucket-list moment and a dream come true. “I was weepy for three straight days,” she quipped.

Though Messing has oft been compared to Ball, because of her comedic style and trademark red hair, she never thought playing Ball was an option.

“Like 15 years ago people would say, ‘Hey, do you want to do like a made for TV movie or something?’ And I always felt like, ‘Oh, I would not even touch that. Like she is untouchable,’” Messing recalled. “But the fact that it was ‘Will & Grace’ doing it … it just felt like the perfect way.”

In fact, the “Will & Grace” homage marks the first time Lucie Arnaz and Desi Arnaz Jr. have allowed their parents’ work to be recreated in this fashion. For the episode, the “Will & Grace” team used the same scripts and recreated iconic moments in “I Love Lucy” history shot for shot, with every detail painstakingly reconstructed.

“That bottle that I held for the Vitameatavegamin [scene] was the exact bottle that Lucy held,” Messing revealed. “That bottle had been in storage for 60 years and our props man was able to get it. … When he told me it was her bottle, I just broke into tears.”

Messing admitted that nailing a perfect re-creation of the Vitameatavegamin scene — her favorite part of the episode — was daunting.

“I only had a week to prepare it and so I was very scared,” she explained. “[Lucy] means so much to me and I just didn’t want to blow it. So I just watched it over — I had to have watched it a 100 times, just analyzing her eyebrow lift and her head tilt and, you know, her lip [movements], and to clock exactly when she would start to get drunk. And then when we were on the set, I would listen to it in my ear. And so I would just focus on the musicality of it, of her voice. And it was the hardest thing I’ve ever had to do for sure.”

Arnaz also made a special cameo in the episode as the boss in the chocolate factory scene.

“We were so overwhelmed with gratitude, and just knowing just how much faith she had in us, it meant the world. And then when she showed up and she just had a smile on her face the whole time,” Messing said. “Then to act with her in the chocolate factory scene, I thought my head was going to explode.”

Since the Emmy winner posted a selfie last November flaunting her incredible transformation into the comedy icon, fans have eagerly awaited the “I Love Lucy” tribute episode, remarking on how much Messing looked like Ball.

“Well, it took three and a half hours to get there. [Make-up artist Elaine Offers] put Elmer’s Glue over my eyebrows so that she could draw it on and then the lips took like 45 minutes. But when the wig went on, all of us just [gasped],” Messing explained. “All of a sudden we saw her coming to life in the mirror.”

In addition to playing Ball, Messing also transformed into Ethel and Fred, the latter transformation taking four and a half hours, with the help of the effects team behind “Star Wars.”

“I’m really, really proud of it,” Messing said of the episode. “It is something that only the four of us have ever been able to experience and have been entrusted with it. And obviously it’s my favorite, favorite episode we’ve ever done and it’s something I will never ever forget.”

And if “Will & Grace” — which caps off its historic 11-season run on April 23 — were to ever receive a similar tribute, Messing’s pick to play Grace would be Amy Adams, who already played her onscreen sister in “The Wedding Date.”

“I’m glad that we were able to give something that people could look forward to and a really good distraction,” she said of the episode airing during the coronavirus pandemic. “Because it really does remind you of a happier, simpler time.”