Lady Gaga
Lady Gaga is receiving treatment for Bronchitis Reuters

Pop superstar Lady Gaga was forced to cancel two concerts at the eleventh hour after developing Bronchitis.

The Poker Face singer had been scheduled to take to the stage at Seattle's Key Arena and the Rogers Arena in Vancouver this week before she was struck down with illness.

Taking to Twitter to apologise to disappointed fans she vowed to make it up to them.

"I'm devastated I'm unable to perform this week. Ursula took my mermaid voice I've come down with horrible Bronchitis," she told her 41.5 million followers.

The 28-year-old songstress' announcement follows speculation that she is secretly engaged to her long-term boyfriend Taylor Kinney after the couple had a pregnancy scare.

"Taylor's been asking her to marry him for the better part of a year, but she never takes him seriously," a source told OK! Magazine.

"Being presented with the possibility of becoming parents pretty much locked down Gaga for marriage."

Gaga's ArtRave: The Artpop Ball world tour concludes in Paris on 24 November.