Delta Goodrem and boyfriend Matt Copley wear tracksuits at Sydney Airport

She is over the moon after her breathtaking duet with Robbie Williams during the AFL Grand Final on Saturday.

And Delta Goodrem couldn’t wipe the smile from her face as she took a flight from Sydney Airport on Tuesday with her boyfriend Matthew Copley.

The Born to Try star waved to the paparazzi as she walked through the international terminal in an off-white tracksuit and designer jacket.

The 37-year-old singer completed her look with gold-rimmed sunglasses and a chain with a padlock pendant, and also sported freshly manicured nails.

Long-haired Matthew, the guitarist for Delta’s band, also took a laid-back approach by wearing a blue tracksuit with a leather jacket.

The couple, who have been dating since late 2017, were seen at the check-in counter with an airline employee before heading to their gate.

It comes after Delta garnered praise for her performance with Robbie for Saturday’s AFL premiere clash between the Sydney Swans and Geelong Cats.

She joined him at the pre-show concert for a duet of his 2000 hit Kids, in which Kylie Minogue originally played the female vocals.

The song rounded out Robbie’s crowd-pleasing set list, which also included Rock DJ, Feel and the ballad Angel, which he dedicated to the late Shane Warne.

Robbie also performed You’re the Voice as a tribute to John Farnham, who was recently diagnosed with oral cancer, and the entire audience sang along.

Reaction to the pre-show has been overwhelmingly positive, with fans saying Robbie and Delta “nailed it” and others even calling it the best grand finale ever.

In contrast, the halftime performance featuring G Flip, The Temper Trap, and several native artists was criticized for poor sound quality and being too “awake.”