The 'Beautiful' singer was joined by her fiancé Matthew Rutler at a Los Angeles gala on Sunday evening (9 November), where she stole the show in a figure-hugging scarlet gown.
Christina, 33, has been keeping a low profile since giving birth to daughter Summer Rain Rutler back in August. What a way to announce your comeback, right?!
A source told E! News that Christina has been enjoying yoga as a means of getting her pre-pregnancy body back. "[She] loves the way it makes her look and feel, inside and out. It's so calming and keeps her centered. She is obsessed!"
The singer and actress - who is also mum to six-year-old son Max - was attending the Breakthrough Prize Awards in California, where she performed her hit song 'Beautiful' for the star-studded crowd.
Other famous faces in attendance included Cameron Diaz and Kate Beckinsale.
The ceremony celebrates the work that scientists are doing.
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