• Share
  • Tweet
  • Share
Christina Aguilera, Breakthrough Prize Awards

Steve Jennings/Getty Images for Breakthrough Prize

She's still got it!

Christina Aguilera flaunted her post-baby bod and her post-baby pipes last Sunday when she attended the Breakthrough Prize Awards Sunday in Mountain View, Calif., with fiancé Matt Rutler.

Xtina took the stage in her plunging red Rubin Singer dress and Marilyn Monroe-esque curls to sing her popular 2002 hit "Beautiful" for the first time since giving birth to daughter Summer Rain in August, and if there was any doubt about whether Aguilera could still hit those incredibly difficult notes—she can.

The blond beauty serenaded a star-studded audience. Seth MacFarlane hosted the event, which was founded by Facebook creator Mark Zuckerberg and brought scientists and celebrities together to raise millions for top scientists. Other celebs in attendance were Kate Beckinsale, Benedict Cumberbatch, Cameron Diaz, Jon Hamm, and Eddie Redmayne

Aside from her heavenly vocals, people couldn't help but acknowledge Christina's fabulous figure, and we learn that's all thanks to simply eating healthy and working out.

A source told E! News the singer "was very healthy throughout her pregnancy and is continuing it now after the baby."

"She is very dedicated to yoga. So much that she has never stopped practicing it. She did yoga the entire time she was pregnant," adds the source. "And Christina has already been working hard on getting her bod back in shape! She is doing private yoga sessions and loves how it makes her feel."

The blond beauty "loves the way it makes her look and feel, inside and out. It's so calming and keeps her centered. She is obsessed!"