Delta Goodrem watches Nick Jonas in concert

Delta Goodrem attended a Nick Jonas concert in California earlier this week.

The Australian singer, who was first romantically linked to musician Jonas in May, reportedly giggled every time he looked at her as she watched him perform at Century City Park in Los Angeles.

The rumoured couple were also spotted on a date last week, watching Les Miserables at the Walt Disney Concert Hall. They were seen beforehand sharing a meal with friends, but 26-year-old Goodrem ordered a cocktail while 18-year-old Jonas was not allowed to drink alcohol.

Jonas has refused to confirm rumours of a romance with Goodrem, but has said that he is "in a really good place" and feels "blessed". Her spokesperson has neither confirmed nor denied press reports of a relationship.

Goodrem and Irish singer Brian McFadden ended their seven-year relationship shortly before she was first photographed with Jonas. When McFadden first heard about the pair, he reportedly warned Jonas that he would be "dead" if he hurt her.

Jonas has previously been romantically linked to stars including Miley Cyrus and Selena Gomez.

Watch the video for Nick Jonas & The Administration's 'Who I Am' below: