Secret Surprise Wedding For Meg Ryan & John Mellencamp?

Meg Ryan and John Mellencamp are back on, and insiders claimed the two are headed for a surprise wedding!

An eyewitness spotted the lovey-dovey couple slipping into the Art Cliff Diner on Martha's Vineyard for breakfast on May 20. Ryan's son, Jack Quaid, and another young woman accompanied the casually dressed off-and-on pair to the quaint local restaurant.

"Meg walked in, headed straight to a table in the corner, and sat with her back turned to all the other diners," the eyewitness told RadarOnline.com.

It's the second time the couple has been spotted together recently. As RadarOnline.com reported, the "Jack & Diane" singer, 65, and the rom-com sweetheart, 55, were caught chatting on a New York street.

"They were just talking," onlooker Stephanie Forman revealed. "They seemed friendly and civil."

That surprise reunion followed Mellencap telling radio host Howard Stern their nearly four-year relationship ended badly, and Ryan "doesn't want anything to do with me."

Mellencamp added, "I loved Meg Ryan. She hates me to death. I think it's because I'm a child. I throw fits. I gripe, I complain, I'm moody. Every bad thing that a fella can be, that's me."

However, sources insisted to RadarOnline.com that things are heating up again!

"They're definitely back together, and John wants their relationship to go full steam ahead. He's even talking marriage!" an insider spilled.

"Meg's a little more cautious, which is why she was trying to keep their reunion a secret. She's lined up a few getaways like this one in Martha's Vineyard to try to rekindle their spark."

"John's a tough man to love, but if it all works out, she's definitely into marrying him this time," continued the insider.

"It's all down to her son, Jack. He loves John, and their split devastated him, so he's been pushing his mom to give John another chance. And so far, so good — John and Meg have been acting like flirty teenagers!"

Their 2014 split became final after Mellencamp was snapped on the street with supermodel Christie Brinkley — just blocks away from Meg's Manhattan digs.