The former X Factor star was beautiful in a flowing patterned gown that highlighted her blossoming baby bump as she took to the stage on Sunday, 31 August for the concert.
Rebecca, 28, was headlining the closing night finale of the Illuminations Switch On event, which was also attended by the likes of Atomic Kitten, Liberty X and 911.
Attendees later praised Rebecca's performance on Twitter with comments including: "Rebecca Ferguson at Blackpool last night. Beautiful woman with a beautiful voice."
Rebecca's performance came after she told fans doctors had advised her to take it easy in the final stages of her pregnancy.
After cancelling a planned trip to Germany, she told fans: "I am now very heavily pregnant with just a few weeks to go. I was advised by doctors I should not fly and without a doctor's consent airlines will not allow me to fly without a note from doctors.
"I was told by the midwife I need to rest as I'm working too hard. My priority is my health and that of my unborn."
Rebecca is just back in the UK from a working holiday to Los Angeles. She flew out shortly after celebrating her 28th birthday, tweeting at the time: "Thankful for another year at 28. Thankful for all I have and all I have achieved. I live the life I always wanted. Caring what other people think. Has robbed me of so many minutes hours and days of what is already a temporary existence #stoppedgivingafk."
She's already confirmed her third child will be a girl named Arabella.
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