The pop star, who welcomed her second child, son Remington, in April (16), was performing for a Facebook Live streaming session when her mind went blank.

Kelly, 34, openly admitted she was "nervous" at the start of the live show, which was broadcast from a studio setting, as she belted out hits including A Moment Like This, Cry, Walk Away, and Beautiful Disaster.

However, the singer appeared to suffer from so-called 'mummy brain' as she forgot the tune and lines to some of her tracks, and had to be reminded by her producer and pianist.

"Lyrics aren't my thing," Kelly laughed, before reasoning, "We wrote a lot of songs. It's been 15 years."

But the singer was worried about how her flubs would be received on social media, smiling as she commented, "I'm gonna get so much crap for this. This is the worst idea!"

Luckily for her, many fans didn't seem to mind the concert mishaps and praised her for her honesty.

"I think it's great that you forget the lyrics," one follower posted. "You're not a robot, you're human and it's a lot to remember. Your voice is so amazing, raw, unfiltered, no magic auto tune! Your (sic) friggen (f**king) amazing!!"

Another added, "Piece by piece is my new favorite song but I love all your music. You're a very talented and down to earth woman. Congratulations on your new addition to your family."