Megan Fox's ex Brian Austin Green tells Machine Gun Kelly to 'grow up'

Megan Fox's ex-husband Brian Austin Green has some tough words for Machine Gun Kelly.

Brian, who was married to Megan for 11 years, didn't hold back when he was asked about her split from Machine Gun Kelly.

The 51-year-old was out getting coffee when TMZ asked him what he thought of Megan and MCK's break-up.

"I didn't even know," he said. "I had no idea."

When he was told that Megan, 38, broke up with MGK, 34, after allegedly finding texts from another woman on his phone, he didn't hold back.

"How old is he? He's in his 30s, isn't he?" he said. "But in your 30s? Like, I don't know, grow up."

He then told how he only wants "the best" for Megan, and the unborn baby she's pregnant with.

"That's a shame,' he said. "I'm heartbroken about it because I know she's been so excited and the kids are so excited for life and the change and all of that."

He continued, "If that's the case - and I don't know the facts of it - but if that's the case it's a tragic situation, and I wouldn't wish that on anybody."

Brian and Megan share three children, Noah, 12; Bodhi, 10, and Journey, eight.

In November, Megan announced she was expecting a baby with MGK, after previously having a miscarriage. It's believed the baby is due in March.