Discovery Communications Inc said it would buy 12 Nordic television channels from Germany's ProSiebenSat.1 Media AG for about $1.7 billion to add fiction and sports to its program offerings.

The acquisition is Discovery's largest ever and gives the company, whose channels include Discovery Channel, TLC and Animal Planet, a firmer foothold in Europe and sweetens the exit for ProSieben's controlling private equity investors.

The sale of the Nordic Channels, one of ProSiebenSat's best performing units, positions private equity investors KKR & Co and Permira -- who together own 88 percent of ProSieben's voting shares -- for a hefty dividend from the German media group.

"It means the private equity owners are able to place up to their full 53 percent stake on the market at some point," said Goldman Sachs analyst Richard Jones.

Discovery also said on Friday it would take 20 percent equity stakes in French television group TF1's Eurosport Group and four pay-TV channels in France and announced a $1 billion increase in stock buybacks.

The purchase extends Discovery into fictional programs and sports broadcasting for the first time.

"This deal also includes our first significant foray into scripted content and the opportunity to manage a suite of nonfiction and fiction brands that bring different formats, personalities and storytelling techniques to our creative culture," Discovery CEO David Zaslav said on a conference call.

Investing in Eurosport was a cheaper option and offered more attractive margins than a foray into the much more expensive U.S. sports market, he said. The Eurosport deal, worth about $221.6 million, gives Discovery the option to raise its stake to 51 percent in two years.

If Discovery exercises this option, TF1 could exercise a put option over the remaining 49 percent, potentially giving Discovery complete ownership of Eurosport.

The $18.2 million stakes in the French pay channels give Discovery ownership in the TV Breizh, Histoire, Ushuaia TV and Stylia channels. Citigroup acted as financial adviser to Discovery.

ProSieben's restructuring paves the way for a KKR and Permira disposal after ProSieben converts its non-voting preference shares into voting common shares to attract a broader investor base for the Frankfurt-listed firm.

The German media group plans a dividend payment of about 5.60 euros per share after completion of the sale, which is expected in the first quarter.

In 2012, the company paid a dividend of 1.17 euros per preference share and 1.15 euros per common share. ProSieben called off an attempt to sell the division last year as offers were too low. Sources have told Reuters that Discovery also was one of the bidders at the time.

In August this year, the German media company said it was looking again at selling after receiving expressions of interest.

ProSiebenSat.1 shares were up 2 percent by 1200 ET, while the broader sector index was down 0.3 percent. Shares in Discovery were nearly flat at $60.18 in midday trading on the Nasdaq.