Prince Harry used laughing gas while Meghan Markle was in labor with Archie.

Harry admits to using the gas in his upcoming memoir, Spare.

Laughing gas is a colloquial term for nitrous oxide, which is a pain reliever used in hospitals.

Meghan bounced on a giant purple ball, used electric candles, and listened to hymns to calm her nerves during labor.

Harry took several hits of the gas and ended up using it all before the nurse came to use it for Meghan.

Meghan received an epidural to help with the pain of her first childbirth.

There was a momentary worry that Archie was potentially tangled in his umbilical cord, but the situation was avoided.

When their daughter Lilibet was born in June 2021, Harry did not use laughing gas because it was not available.

Harry's memoir, Spare, will be released on January 10 by Penguin Random House.