Megan Fox Makes First Appearance at GQ Party After Pregnancy Announcement

Megan Fox made her first appearance after her big baby announcement ... but it was only from the neck up so you couldn't see her belly.

The actress, who our sources say is 4 to 5 months along in her pregnancy, and her rock star boyfriend, Machine Gun Kelly, rolled up in a Rolls-Royce to the Chateau Marmont in L.A. for the GQ Men of the Year 2024 party.

MGK stepped out of the car and went inside the event, leaving Megan in the backseat with a driver and a security guard in the front seats.

Check out the photo ... Megan's head and beautiful face are in full view -- but her body is completely blocked so no one can sneak a peek at her baby bump.

As we reported Monday ... Megan announced she's expecting her first child with MGK in an Instagram post with a photo of her covered in black paint while displaying her protruding tummy.

She also uploaded an image of her positive pregnancy test and tagged MGK, writing in the caption, "Nothing is ever really lost. Welcome back 👼🏼❤️".

Our sources say she's expecting to deliver the baby in March.

Meanwhile, back at the Chateau Marmont, Megan waited for 45 minutes in the Rolls Royce before MGK exited the soiree and jumped in the car, which drove off.

Other celebs who attended the bash were Dwayne "The Rock" Johnson, Tyler the Creator, John Mulaney, Pharrell Williams, Katt Williams, Naomi Osaka, Big Sean, Anderson .Paak, Quavo, Offset, YG and many more.