Olivia Culpo thought Nick Jonas was going to propose to her.

Olivia Culpo and Nick Jonas

Olivia Culpo and Nick Jonas

The 22-year-old singer made his girlfriend "panic" during his performance at the annual Miss Universe pageant when he got down on one knee in front of her.

He said: "I went down and sang to her and I got on a knee and sort of approached her.

"Her face was in full panic - she thinks I'm going to propose on national TV in front of the whole world! One billion people watch that."

When asked if he would propose to the beauty queen, he added: "We're 22, so there's plenty of time to do that. We are very happy."

Meanwhile, Nick also revealed that his song, 'Jealous', was inspired by his relationship with Olivia.

He shared to The Sun newspaper: "The song came about nine months into our relationship. Someone kept staring at her and it was kind of uncomfortable because we were clearly on a date. It was such a disrespectful situation.

"We were at the beginning of our relationship, so I would have those moments of feeling nervous and jealous.

"The song is a topic many men are afraid to talk about. It's vulnerable and it's a weird position to be in. But instead of getting frustrated, I went to the studio and wrote the song the next day."