WebMD Health Corp. confirmed today that KKR’s Internet Brands has offered to pay $2.8 billion to acquire the health services company.

Internet Brands will pay $66.50 for each WebMD share, which closed last Friday at $55.19. The companies emphasized that the price is a 30 percent premium on WebMD’s share price from February 15, which was a day before it announced plans to consider “strategic alternatives.”

WebMD’s stock jumped 18.68 percent to $65.75 after the deal was announced this morning.

“After a thorough review of strategic alternatives, we are pleased to announce this transaction, which provides our stockholders with immediate and significant cash value and a substantial premium,” said Martin J. Wygod, chairman of WebMD, in a statement. “Throughout this process, our Board has conducted diligent analysis and thoughtful deliberations. WebMD and its financial advisors had a process that involved outreach to more than 100 strategic and financial parties, and we are confident that this transaction maximizes value for our stockholders.”

Reuters broke rumors over the weekend that a deal was in the works. The companies said they expect the deal to close in the four quarter.

WebMD is a Dot Com 1.0 survivor, having been founded in 1996 by Netscape cofounder Jim Clark and Pavan Nigam as Healthscape. The company later changed its name to Healtheon and after it bought WebMD in 1999, it adopted the latter’s name.

The company went public in 2005 and has soldiered on through numerous technological shifts. But in February, it issued a disappointing outlook and said it had hired J.P. Morgan to explore a possible sale. There were some doubts about whether anyone would want this 21-year-old survivor.

But the deal with Internet Brands makes some sense. Internet Brands owns a number of similar sites, such as DentalPlans.com, VeinDirectory.org, and AllAboutCounseling.com. So this acquisition will give it a wider medical portfolio.