Melissa McCarthy suffered a mysterious allergic reaction while living in Australia.

The actress has been Down Under for the past few months while shooting the TV series “Nine Perfect Strangers”, but it hasn’t all been fun and games. McCarthy tells Ellen DeGeneres during an appearance on her show Thursday how her body blew up in size after something bit her while she was sleeping.

Revealing how she now has to carry an EpiPen, McCarthy shares: “Something bit me here and 92 per cent of my body blew up in a way that I didn’t know was possible. I carry an EpiPen because nobody knows [what it is], it could be anything.

“[They said it] could be one of a thousand things, I’m like ‘great.’ It got me during the night, my lip was about four times the size. I kept trying to say ‘I think something’s wrong,'” but adds that she couldn’t because of the size of it.

McCarthy jokes of her husband Ben Falcone, “His first response was ‘get away from me’ because what if it’s contagious?”

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She also reveals Falcone, who she’s been married to since 2005, has a “huge crush” on Harry Styles.

As DeGeneres mentions she understands Falcone has a crush on someone, McCarthy replies: “He’s fallen pretty hard for Harry Styles.”

DeGeneres responds, “Who hasn’t? I think everyone is in love with Harry Styles.”

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Plus, McCarthy plays a special version of one of DeGeneres’ favourite games, “Drawer Dash Down Under!” See more in the clip below.