Disney will be forced to acquire all of Sky if 21st Century Fox’s takeover of the UK pay-TV broadcaster is not complete prior to the Mouse House’s takeover of the rival Hollywood studio.

The UK’s Panel on Takeovers and Mergers made the ruling on Thursday morning and the three companies have accepted it.

Disney will have 28 days from the completion of its $66B acquisition of Fox to make a £10.25 ($US15) offer for all the shares of Sky if Fox’s own $15.7B takeover of Sky is not complete by then or if Comcast’s rival offer has not been accepted. It also posits that this would not be required if another third party has acquired 50% of Sky by then.

Fox said that it believes its deal for Sky will close by June 30 2018 and is confident that the UK’s Competition and Markets Authority will approve the transaction so it will be interesting to see which mega-deal moves first. Fox currently owns 61% of Sky and is in the process of buying the remaining shares.

“Disney will be required to make a mandatory offer to the holders of ordinary shares in Sky pursuant to Note 8 on Rule 9.1 of the Takeover Code as a result of Fox’s stake of approximately 39% in Sky. The basis for this ruling is that, in accordance with paragraph (b) of Note 8 on Rule 9.1, the Executive considers that securing control of Sky might reasonably be considered to be a significant purpose of Disney’s acquiring control of Fox,” the independent body noted.

Tick, tock.