Outfit repeating is in. Here's how to do it well, according to Christian Siriano.

• Re-wearing outfits is popular at red-carpet events and in everyday life.
• Christian Siriano wants people to embrace repeating outfits they love.

It's official: Re-wearing outfits is in.

While "outfit repeater" was once an insult hurled at Hilary Duff's character on Disney Channel's "Lizzie McGuire," re-wearing items of clothing has even become a red-carpet trend with celebrities including Emma Stone, Cate Blanchett, and even Kate Middleton recycling their looks from years past.

Just ask Christian Siriano, who's dressed numerous celebrities for red-carpet occasions. The 38-year-old designer and past "Project Runway" winner is gearing up to host a Wardrobe Refresh Hotline event on TikTok Live as part of his partnership with Persil laundry detergent. Beginning June 26 at 6 p.m., Siriano will take live questions on Persil's TikTok account about re-styling outfits and maintaining the quality of beloved pieces.

"I love the idea that if you have something that you love or loved before, why are you not recycling your wardrobe?" Siriano told Business Insider. "Even actresses are saying now, 'It's OK to re-wear things, even on the red carpet,' so if you're just in your day-to-day life, why not?"

Siriano attributes the popularity of repeating outfits to efforts to curb overconsumption, hearkening back to a time when people had smaller wardrobes comprised of quality items that would last.

"I make clothes that are special and unique. So yeah, you're not going to wear this every day," he said as he gestured to a sparkly pink tulle piece behind him, "but I don't want you to not wear it ever again. I want you to be able to wear your special Christian Siriano gown to other things throughout your life."

Rewearing looks can also be a status symbol if the item is no longer available, Siriano said.

"I think it's kind of cool if you're with your friends and you're all hanging out and everyone's like, 'Oh my God, I love that jacket,' and you're like, 'Oh yeah, I bought it at a vintage store 10 years ago and I love it,' and people are jealous because they can't get it," he said.

Here are some of Siriano's top tips for repeating outfits with style.

Use accessories to change up an old outfit

Accessories can help breathe new life into an outfit that has been worn again and again.

"The idea here is, how do you make it new and fresh and feel different?" Siriano said. "I think that it's all about your confidence and how you can put a look together. So it's your bag, it's your shoes, it's accessories, hair and makeup."

Style the look — don't just wear it

Re-wearing a piece of clothing doesn't have to mean wearing it exactly the same way as last time.

"If you bought a beautiful blazer that you used to wear to work every single day, maybe you should wear it when you go out to dinner, and belt it and make it a dress," he said.

Forget the fashion 'rules'

Wearing an outfit again doesn't have to be a complicated decision. If you like it, wear it, regardless of what you perceive the rules or etiquette to be.

"It shouldn't be so scary like, 'Oh my god, can I wear this dress? I wore it last week,' Siriano said. "Yes, of course you can."