Machine Gun Kelly celebrates his birthday with Megan Fox, Kourtney Kardashian and Travis Barker: 'I’ll grow up next summer'

Machine Gun Kelly enjoyed his birthday in celebrity style with girlfriend Megan Fox and couple Kourtney Kardashian and Travis Barker.

On Friday, the "Rap Devil" singer posted photos of his 31st birthday party, notably one in which he cuddled up to Fox, 34, his girlfriend of nearly one year. Also included in the pic were new couple Kardashian, 42, and Barker, 45. "I’ll grow up next summer...SINcerely, birthday boy," Machine Gun Kelly captioned his photo. On her page, Fox shared a portrait of the couple writing, "Happy Birthday blonde angel baby."

It's not the celebrity foursome's first outing — last month, they headed to Enterprise, Nevada to watch a UFC fight, then to the Cosmopolitan Hotel for a Blink-182 performance.

Fox, who shares three children with ex-husband Brian Austin Green, told Nylon last November that her romance with Machine Gun Kelly is a "once in a lifetime thing" and that "Loving him is like being in love with a tsunami or a forest fire."

She added, "The intensity of merging with him is just overwhelming, and the threat it poses is so powerful but so beautiful that you have no choice to surrender with reverence and with gratitude." The couple only met last year on the film set of Midnight In The Switchgrass and grew close while production paused for two weeks. Fox also appeared in the singer's May music video for the song "Bloody Valentine."

While Kardashian, who also shares three children with her ex-partner Scott Disick, began dating Barker in January. Recently, they celebrated their love for each other on social media — Barker showed off a tattoo he made in Kardashian's name and to celebrate her birthday this week, the rocker posted a photo of the pair kissing. "YOU’RE A BLESSING TO THIS WORLD," he captioned the Instagram pic.

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