The Saturdays singer was pictured looking radiant and smiling from ear to ear as she left the BBC Radio 2 studio in London alongside husband Marvin.
Rochelle, 27, and Marvin, 31, announced on Thursday that they're expecting a little brother or sister for daughter Alaia-Mai, three.
The couple both posted their happy baby news to social media, eliciting a string of congratulatory messages from fans and famous friends, including Tulisa Contostavlos and Rochelle's The Saturdays co-stars.
Rochelle later said: "Thanks so much for everyone's kind msgs. We are over the moon. Alaia is SO excited to be a big sister. Roll on the spring."
The singer-turned-TV presenter has often said she wanted to expand her family with Marvin but they'd been waiting for the right time, as they have such busy careers.
While The Saturdays are currently on hiatus, Rochelle has been designing her own fashion range with Very.co.uk, presenting TV shows including Ninja Warrior and the last series of The Xtra Factor.
Marvin, meanwhile, shot to fame as a member of JLS but these days works with dance group LuvBug, hosts his own radio show and co-presented three series of The Voice UK.
Speaking to Reveal last year, Rochelle said: "It's one of those things. When you get married, everybody asks you when you're going to start a family. Then, when your baby is a week old, they ask you when you're going to have your next one. I have absolutely no idea. It's not something I plan and I don't know if it will be easy [to conceive].
"I also don't know how I would work, be pregnant and juggle a two-year-old. I don't know how I would cope. We definitely want to, but it's not really on the agenda just yet."
Rochelle and Marvin are returning to TV this evening to co-host Children In Need.
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