The 38-year-old, who announced she was pregnant with her first child in early September, looked stunning in a floor-length gold gown with a visible baby bump.
The TV presenter was with her other half Patrick Kielty, 44, as she dished about the upcoming milestones in her pregnancy.
Speaking to E! about finding out the sex of her baby, Deeley said: "We don't know yet - but I think we will find out.
"I'm 38 and it's going to be a real change for us. I think it's going to be nice to find out if it's a little girl or a little boy and call it he or she rather than it."
When asked if she'd had any pregnancy cravings yet, she added: "No, I'm all actually fine. Not too bad at all."
Deeley also admitted she had to make a few alterations to her sequinned gold gown before hitting the red carpet.
She added: "I have managed to squeeze myself into this Monique Lhuillier gown. We had to let out the back a bit though."
Deeley revealed she was expecting her first child with Kielty via Twitter on 3 September.
She tweeted: "Exciting news... Paddy and I are so happy to be expecting our first child in the spring... Lucky us."
Paddy and I are so happy to be expecting our first child in the Spring..... Lucky us.— Cat Deeley (@catdeeley) September 3, 2015
The pair first met when they presented talent show Fame Academy together in 2002 but didn't go public about their relationship until March 2012. They married in September 2012.
See more photos of Deeley and Kielty at the Emmy awards below.