Mila chose a billowy, sleeveless navy dress that made the most of her long legs, teamed with sequined high heels. She wore her hair long and straight and opted for natural makeup.
Mila kept her baby bump concealed
As she smiled for the cameras, she kept an arm strategically placed across her stomach, gently resting her hand on Channing's chest.
The Hollywood stars were attending the screening of their sic-fi thriller at the 2014 CinemaCon at Caesars Palace in Las Vegas. It was Mila's first red carpet appearance since the news broke that she is pregnant.
Ashton, 36, and Mila have been dating for around two years, and got engaged in February.
Mila and co-star Channing Tatum smiled and laughed on the red carpet for a screening of their new film Jupiter Ascending
There are mixed reports about their plans to tie the knot.
According to the Sun, the cute couple want to get married in April, before "their new bundle of joy arrives", and are keen to have the ceremony in a registry office to speed up the process.
"They are planning to get married in LA in April," a source said. "They just want it to be made legal so are happy with a registry office.
The cute couple got engaged in February
"Mila, especially, wants it to be very low-key, with just their family there and a BBQ in their garden afterwards. She doesn't want to do anything showy or over the top."
But a source has insisted to E! News that reports the pair are rushing to the altar next month are simply "not true".
Reports that the couple will be tying the knot as soon as possible are said to be simply "not true"
Regardless of their plans to marry, Ashton and Mila can't wait to become parents. "They are happy, healthy and excited to star a family," an insider told US Weekly.