Cable TV giant Comcast says it is considering a takeover offer for Rupert Murdoch's 21st Century Fox, setting the stage for showdown with Walt Disney.
Disney has agreed to pay $52.4bn for Fox, but Comcast said it was in the "advanced stages" of preparing a better bid.
Any offer would be "all-cash and at a premium" to Disney's all-share offer, Comcast said in a statement.
But the US firm, which owns NBC, said no final decision had been made.
Rumours about Comcast's interests in Fox have circulated for weeks, but it is the first time it has confirmed its intentions.
Like Disney, it wants to buy all of Fox's assets except its news channel and main sports and business networks.
That would include the 20th Century Fox film studio, the Fox television network and the Asian pay-TV network Star TV.
It would also include a 39% stake in Sky, for which Comcast tabled a separate bid in April, taking it into direct conflict with Fox, which wants to acquire the British broadcaster outright.
Any takeover attempt by Comcast would be likely to face regulatory scrutiny, as will Disney's offer.
The US government is currently suing to block a merger between Time Warner, and the telecoms giant AT&T.
Experts say the firm would be unlikely to proceed with an offer for Fox until a judge rules on that case in June.
However, in its statement, Comcast promised to pay a significant break fee should regulators scupper a deal. It said this "would be at least as favourable to Fox shareholders" as Disney's offer of $2.5bn.
The fight for 21st Century Fox comes as traditional media groups scramble to consolidate in the face mounting competition from online challengers like Netflix and Amazon.
It has driven broadcast giant CBS to try to merge with Viacom, which owns the MTV and Nickelodeon television stations.
It has also spurred AT&T's $85.4bn offer for Time Warner, whose assets include pay TV channel HBO.
However, analysts believe such tie ups will face close scrutiny from US regulators who fear consolidation could drive up prices for consumers.