Heroes star Hayden, who is expecting her first child with fiancé Wladimir Klitschko, was promoting the TV series on Monday (15 September) in Los Angeles.
Hayden beamed from ear to ear and couldn't stop smiling as she lovingly cradled her growing baby bump.
While her bright red dress accentuated her rounded stomach, Hayden teamed her frock with towering silver peep toe heels.
At the 66th Primetime Emmy Awards last month (25 August), Hayden let slip during a red carpet interview that she is expecting a baby girl!
"I'm thrilled for her to come out," she accidentally blurted out. "I just said that, didn't I?"
Hayden announced her pregnancy last month while taking party in the ALS Ice Bucket charity challenge.
Hayden plays rising country singer Juliette Barnes in the hit show Nashville, which broadcasts in the UK on More 4.
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