Sir Ian McKellen got down on one knee and ‘proposed’ to Sir Derek Jacobi after hearing marriage equality was one step closer to reality.

The Gandalf actor had been filming an episode of the new TV series Vicious, based on the 1960s play Staircase, at London’s South Bank studio.

On 5 February, the House of Commons voted for same-sex marriage in England and Wales.

‘Since we can now…’ said McKellen, as he knelt in front of Jacobi. The gag was met with laughter and applause from the studio audience.

‘A lot of people my age don’t want to get married and think one of the advantages of being gay is that you don’t have to,’ McKellen said in the May issue of Attitude.

‘Yet we have a Prime Minister who, against the odds, is appealing not just to gay people, but to what the country seems to have accepted.’

In the sitcom, filmed in front of a studio audience, Jacobi and McKellen play a couple of 48 years who live in central London.

When the actors were 18 and 19 at university, McKellen admitted to having a ‘massive crush’ on Jacobi.

Vicious will be broadcast on UK’s ITV in late April this year.