The racy snap was taken from her recent pictorial for Allure magazine, which saw famous mums including Kristen Bell and Jenna Dewan-Tatum strip off for the Nudes feature.
"If you want people to stop talking about how you look in a bikini, let them see you naked," the actress captioned the picture. "It tends to shut them up :)"
Minnie only returned to Twitter this week, after announcing she was leaving 'Twittersphere' on April 9. Her decision came in response to a number of tweets she received after photos were published of her in a bikini on holiday.
"God some people are horrible: you try being photographed when you don't know it's happening, when you're on holiday with your kids," she wrote.
"I'm out of this Twittersphere for a while. It's too mean sometimes, about your body, about your soul. Not worth it."
The About A Boy star announced her return to the networking site on Monday, tweeting, "Right, where was I. Oh yes — Aristotle: 'To avoid criticism, say nothing, do nothing, be nothing.' In deference to this, I think I'll carry on."
Meanwhile, Minnie stepped out with a very special date at the City Year Los Angeles's Spring Break: Destination Education fundraiser over the weekend: her son Henry.
Minnie with son Henry Story Driver
It was the five-year-old's first time on the red carpet, and he happily posed for photographs with his proud mum.
"He is having the time of his life," Minnie told People. "It's way past his bedtime. He is definitely going to fall asleep on the car ride home. But he's having such a good time!"