Channel 4 is to make digital channel E4 available on the non-subscription Freeview service in time for the new series of Big Brother next month.
The finale of the last series of Big Brother attracted 9m viewers
Aimed at the youth market, shows on E4 include The OC, Smallville, ER and award-winning UK sitcom Peep Show.
Channel 4 hopes the increased audience numbers will bolster advertising revenue, offsetting the loss of any subscription revenue.
The sixth series of Big Brother is due to kick off at the end of May.
There are currently five million homes in the UK with Freeview.
ER (pictured) and The OC are among the draws for current E4 viewers
E4 will continue to be broadcast on cable TV and satellite, but operators will no longer be required to pay Channel 4 a subscription fee.
The channel will also be removed from the Top Up TV package that is marketed as an add-on to Freeview.
The expansion of C4's multi-channel offerings follows chief executive Andy Duncan's call for an extra £100m in public money to help the channel make the transition to digital television.
Channel 4 is currently in talks with Big Brother creators Endemol about commissioning further series of the reality TV show.
The current agreement is due to expire this summer with the conclusion of Big Brother 6.