Machine Gun Kelly Calls Megan Fox His 'Ethereal Light Being' In Sweet Birthday Tribute

The musician penned a sweet message to the actress on Instagram.

It's been a busy week for Machine Gun Kelly and Megan Fox, but the musician didn't let the actress' birthday slip through the cracks. The 32-year-old artist took to Instagram on Monday to share a sweet message for his fiancée.

"Wishing the happiest birthday to my ethereal light being," Kelly wrote alongside a series of photos that encapsulate their relationship. "I love you maki."

While the couple was recently in Las Vegas for the Billboard Music Awards, where Machine Gun Kelly gave an epic performance dedicated to Fox and their "unborn child, the Transformers actress told ET that they were "going away into the desert" with "no cell phones" for her birthday.

Fox, however, managed to post a tribute to Kelly on Instagram before their phone-free excursion began. "Baby- so proud of you for giving such a vulnerable and emotional performance. You are magic," she gushed over her guy. "Also Vegas it’s been nice but you are my version of the innermost ring of hell. Off to the wilderness for my birthday. No one talk me for a week."

Following Kelly's performance where he alluded to the fact he and Fox are already married and possibly adding to their family, the Jennifer's Body star revealed one way they spent their time in Sin City -- by cutting up an outfit she wore in order to have sex.

"Was this blue outfit expensive because we just cut a hole in the crotch to so we could have sex," a text from Fox to what appeared to be her stylist read, to which the fashion guru replied, "I hate you. ...I'll fix it."

Fox also added in the same post on Monday that she spent quite a bit of time "crying in the shower" while in Vegas. 

"An introvert in Vegas for three days during eclipse season…just SO much crying in the shower," she wrote.

ET caught up with Kelly and Fox on the red carpet at the Billboard Music Awards on Sunday, where the musician opened up about performing "Twin Flame," the song he wrote for his wife.

"I wrote this song two years ago exactly today," Kelly shared. "I played it for her, it's all a trip, it's like it's all meant to be."

"Yeah there's like super special secret meaning to the song as well," Fox added. "So I'm sure I will be [emotional], but I can't cry and f**k up this eyeliner."