Christina Aguilera makes stunning return to red carpet MOUNTAIN VIEW, Calif., Nov. 10 (UPI) -- Christina Aguilera made her post-baby return to the red carpet Sunday. The 33-year-old singer and fiancé Matthew Rutler attended the Breakthrough Prize awards in Mountain View, Calif. Family Guy creator Seth MacFarlane hosted the ceremony, which honored achievements in fundamental physics, life sciences and mathematics. Aguilera stunned in a low-cut, curve-hugging red dress that accentuated her cleavage and small waist. The star gave birth to daughter Summer Rain in August, and reportedly practices yoga and eats healthy to keep in shape. Aguilera and Rutler have been together since late 2010, and got engaged in February. The singer was married to music marketing executive Jordan Bratman from November 2005 to April 2011, and has a six-year-old son named Max from the relationship. Aguilera released her seventh studio album, Lotus, in 2012, and has served as a coach on NBC reality competition The Voice for four seasons. The star is currently on leave to care for baby Summer, but will return for season eight in 2015.