The speed with which Comcast's Brian Roberts returned with a higher offer was created to show how determined he is to buy the group which is present in 23 million homes across Europe.
Fox shareholders are scheduled to vote on the Disney deal on July 27.
Chaplin fears that Comcast could overpay for Sky and possibly Fox, leading to tough ramifications for the company's stock price.
Comcast said its cash offer has been recommended by Sky's independent committee of directors and that it has committed the financing required for the deal.
Reuters is reporting that Comcast is doing it now so that Fox shareholders won't have antitrust concerns, plus increase their chances for uprooting Disney's bid.
The skirmish for control of Sky is being fought in the shadow of an even bigger battle - a struggle for control of prized entertainment assets owned by Fox, including its stake in Sky. At present, Disney appears to have the upper hand in the contest for Fox, stirring speculation that Comcast will redirect its firepower into snatching away Sky as a standalone acquisition.
The British government is expected to finally allow Fox, which is run by Rupert's son James, to buy Sky this week, after the US group agreed to sell Sky's award-winning news channel to Disney to prevent Murdoch from owning too much of the British media.
The company says this is 12 percent higher than the last bid from Comcast and values Sky at 24.5 billion pounds ($32.5 billion). "We will be posting our offer document to Sky shareholders shortly". Sky is a pawn in a wider contest between Comcast and Walt Disney Co. for the bulk of Murdoch's media empire, as the U.S. media giants try to take on powerful digital rivals like Netflix Inc. The opposition has not completely subsided despite the plan to spin off Sky News.