President Barack Obama is set to deliver his farewell speech as President of the U.S. later on Tuesday.

After eight years in the White House, Obama will deliver his swansong from his adopted home city of Chicago at 3 a.m. Nigerian time.

The speech which is expected to be a “serious speech” and not a “rally”, according to sources close to President Obama, is expected to offer a series of “warnings” directed squarely at President-elect Donald Trump.

While he is likely to offer a defence of his signature “Obamacare” health insurance reforms and his record on the economy, the headline-making part is expected to be “a series of admonitions about the challenges we face moving forward”, according to a loyalist.

Details of what the speech will be about are still speculative.