Tina, who is six months pregnant, is expecting a baby with her boyfriend Paul Cashmore.
The 39-year-old thanked fans for their well-wishes, explaining that she didn't think anything could top her reunion with S Club 7 last year.
'Reach' singer Tina tweeted: "I didn't think last year could be topped #BringItAllBack2015 but this year just got even more amazing thank u 4 all your kind words."
Tina and Paul, an investigator as seen on Channel 4's Hunted, have been together for three years.
The couple already know the sex of their baby but are keeping it a secret.
90s pop group S Club 7 first reunited in November 2014 after a 12-year hiatus to perform a special medley for Children In Need. They then announced an arena reunion tour kicking off the following year.
The group - Tina, Paul Cattermole, Jon Lee, Bradley McIntosh, Rachel Stevens, Hannah Spearritt and Jo O'Meara - rose to fame in 1998 after starring in their own hugely popular BBC television series Miami 7, and went on to achieve four number one hits.
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