Comcast sees Sky's 23M customers in the UK, Italy and Germany as a platform for further growth on the Continent. "We have long believed Sky is an outstanding company and a great fit with Comcast".
Comcast confirmed its bid at £12.50 a share, as first proposed in its approach two months ago, which marks a 16% increase on the £10.75 a share offered by Fox to buy the 61% of Sky is does not already own.
Mr Murdoch's 21st Century Fox said it was "considering its options", but "remains committed to its recommended cash offer for Sky".
Shares of Comcast went up by almost 3% on Wednesday already reaching a high of $34.78 after closing on Tuesday at $33.35. Fox can only sell its stake with the approval of Disney, which may help Fox back a new, higher bid for Sky.
It said it would expect the deal to complete before the end of 2018.
In order to receive regulatory clearance, Comcast has made a range of commitments, including maintaining Sky News's annual expenditure for ten years.
On Wednesday's earning call with investors Roberts said that Comcast loves its position of being both an owner and distributor of content and is impressed by continued momentum in Sky's business, which is a company that looks very similar to Comcast.
The deal has been held up by concerns about the influence Murdoch could wield over public opinion through owning all of the broadcaster as well as British newspapers including The Times and The Sun.
Comcast also promised not to buy a majority interest in any United Kingdom newspapers for five years and committed to maintaining Sky's headquarters at its current site in Osterley, west London, for five years. The stock closed up nearly 4 percent at £13.59. Sky is arguably the most equivalent company to Comcast outside of the US.
It partly reflected expectations among investors that Fox and Comcast - along with potential other suitors - were likely to enter a bidding war. Sky has a strong business, excellent customer loyalty, and a valued brand.
"As far as the value of Sky goes, that's a game changer".
"The group looks on course to deliver operating profits of £1.5bn this year, double what it earned 10years ago".
Fox, which already has a 39 percent stake in Sky, said in a statement that it "remains committed" to its offer and "is now considering its options".
On Wednesday, Sky also welcomed commitments the USA cable giant had made to address potential public-interest concerns over Sky News, its influential 24-hour news channel.
Comcast, which owns cable channels MSNBC and CNBC, has already said it believes its approach would escape concerns over media plurality because of its "minimal presence" in United Kingdom media.