Singer Adele's highly anticipated follow-up album to "21" that was expected to arrive early this years, has reportedly been delayed until the second half of 2015.

"The album will be released when it's ready, (we) hope that will be at some stage in 2015," said a source.

Another source added that "logically, there is now almost no chance" of the record being ready for release before the second half of 2015, reports aceshowbizz.com

The blockbuster "21" has sold more than 30 million copies in America since being released in 2011. It spawned mega hits like "Rolling in the deep", "Set fire to the rain" and "Someone like you".

Fans first hoped that a follow-up record would come in late 2014 after Adele tweeted a cryptic message on her 26th birthday last May.

At that time, she wrote: "Bye bye 25... See you again later in the year x." However, last year's financial reports by her label, XL Records suggested that no Adele album was planned for 2014.