* Austria's Spielberg circuit set for return next year
* Calendar could be a record 22 races (Adds background)
VIENNA, July 23 (Reuters) - Formula One will return to Austria next year after an 11-year absence, world champions and Spielberg circuit owners Red Bull said on Tuesday.
The energy-drink company said a deal had been struck between Red Bull's billionaire founder Dietrich Mateschitz and Formula One's 82-year-old chief executive Bernie Ecclestone.
"Dietrich Mateschitz and Bernie Ecclestone have reached agreement to the effect that Formula One will come back to Styria next year," Red Bull said in a brief statement issued in Austria.
"On condition of approval by the required authorities, July 6, 2014 is expected to be the date."
Austria last hosted a grand prix in 2003, after which the circuit was due to be extended, but construction work was stopped midway and the track became unusable for years before Mateschitz bought and rebuilt it, renaming it the Red Bull Ring.
The circuit has hosted junior series and German Touring Car (DTM) races in recent years.
Mateschitz, who founded Red Bull with two Thai partners in 1984, is one of Austria's richest people, with a net worth of $7.1 billion, according to Forbes.
There was some speculation last December that Spielberg could return even earlier, with Ecclestone leaving a July 21 slot open for a mystery European race in 2013 that was ultimately left vacant.
Ecclestone said subsequently that the slot had been intended for Turkey's return, which fell through, but it could also have allowed Austria to have a back-to-back race with Hungary, whose round is this weekend.
This year's German Grand Prix was held on July 7, with Hockenheim due to host that country's race in 2014 as part of an alternation with financially-troubled Nuerburgring.
If Spielberg is confirmed for the July date in 2014, it could be at the expense of another European race - with Hungary another possible candidate for alternation given the proximity of the two venues.
Austria was paired with Germany in the past, before switching to May for its last few years. The 2002 grand prix became infamous after Ferrari ordered Brazilian Rubens Barrichello to let Michael Schumacher win.
Formula One has 19 races this season but is already due to introduce two new grands prix in 2014 - one at Russia's Winter Olympic venue Sochi and the other in New Jersey with the Manhattan skyline as a backdrop.
New Jersey, whose race was originally scheduled for this year and still has a question mark over it, has talked of a June race while Sochi's mayor said in January that his city's grand prix would be held in November.
Ecclestone is due to present a provisional calendar to the governing FIA's World Motor Sport council in September. (Reporting by Georgina Prodhan/Alan Baldwin; Editing by Clare Fallon and Justin Palmer)