Hugh Jackman and his girlfriend Sutton Foster have been roasted online after performing a 'cringeworthy' loved-up duet on stage.

The musical theatre stars recently appeared at the Ogunquit Playhouse in Maine for a benefit gala and stunned the crowd by performing a duet of the ballad A Million Dreams from Hugh's 2017 film, The Greatest Showman.

Hugh, 57, and Sutton, 51, beamed as they swapped verses of the love song, repeatedly locking eyes as they sang to one another.

The pair, who starred together in the Broadway revival of The Music Man before their relationship turned romantic, appeared to relish the chance to perform side-by-side again.

But while the couple appeared to throw themselves into the sentimental performance, their on-stage chemistry left some viewers unimpressed, with social media users describing the rendition as 'cringey' and hard to watch.

'I'm sure they are both lovely people but the cheese is just too much!' one person quipped.

'Dreadful! So off-key, both dire,' a second added.

'Seems like this is the wrong key for both of you,' another chipped in, as someone else wrote: 'They don't sound great, do they?' 

During the performance, Hugh looked dapper in a stylish monochromatic look, consisting of a white dress shirt and black pants.

Meanwhile, Sutton dazzled in an elegant yellow plunging sequined gown.

The duet comes after it was reported that Hugh and Sutton were struggling to strike a work-life balance while their romance blossoms.

An insider told Woman's Day the couple were lacking 'quality time together'.

Hugh's full slate of work commitments has given Sutton some empathy for what his ex-wife may have experienced in their marriage, the source alleged.

'He's a workaholic and she's starting to understand how lonely Deb must have felt at times.'

Sutton is also busy with her own career, in addition to raising her daughter, Emily Dale, nine, whom the American actress shares with her ex-husband, American screenwriter Ted Griffin.

'Sutton's finding it hard to be by Hugh's side at so many events and he invites her to every single one,' the insider continued.

'It's not that she's shy, but she's busy with her own career and still has a young daughter to raise.

'Sadly, the biggest casualty of all is Hugh and Sutton finding quality time together.

'They're like passing ships sometimes.'