Former New Jersey Gov. Chris Christie has appeared in a national ad promoting the importance of wearing a mask or face covering during the pandemic.

Christie, a Republican, spent a week in the ICU earlier this year after contracting COVID-19. He previously said that he believes that he contracted the virus after visiting the White House to help President Donald Trump prepare for a debate against Joe Biden.

"This message isn't for everyone. It's for all those people who refuse to wear a mask. You know, lying in isolation in the ICU for seven days, I thought about how wrong I was to remove my mask at the White House," Christie said in the ad. "Today, I think about how wrong it is to let mask-wearing divide us, especially as we now know you're twice as likely to get COVID-19 if you don't wear a mask. Because if you don't do the right thing, we could all end up on the wrong side of history. Please wear a mask."

Early on in the pandemic, Gov. Phil Murphy issued an executive order that all New Jerseyans must wear masks while out in public indoors. Masks are encouraged for outdoor use in situations where social distancing is difficult.

The Centers of Disease Control and Prevention also recommends that everyone wear masks to slow the spread of the virus.