She has been recognised for services to drama and to charity.
The veteran actress said: “Thank you for the award. It is a great honour and I would like to thank Her Majesty, and all those involved in my recommendation.”
Brown, 94, was previously made an MBE in the Queen’s Birthday Honours in 2008 for services to drama and charity.
She served in the Women’s Royal Naval Service at the end of the Second World War, and then left to train at London’s Old Vic Theatre School in Lambeth.
Before joining EastEnders in 1985, Brown appeared in a spate of TV shows including Coronation Street (1970-71), where she played Mrs Parsons, and The Duchess Of Duke Street (1976), where she starred as Mrs Leyton.
Brown debuted devout Christian and hypochondriac Dot Cotton in 1985 to 1993, and then returned in 1997 before finally leaving the show in 2020.
On January 31 2008, she single-handedly starred in an episode called Pretty Baby.
She spoke to a cassette recorder about her life so that her husband Jim could listen to it as he lay in hospital following a stroke.
Brown won numerous awards for her character – mainly as a result of her on-screen relationship with Jim, played by John Bardon.
These included best on-screen partnership at the British Soap Awards in 2002 and 2005.
She also won in the best storyline category at the 2001 Inside Soap Awards for her schizophrenia storyline and a lifetime achievement prize at the British Soap Awards in 2005.
In 2010, Brown took part in the Strictly Christmas special, where she danced the tango with Vincent Simone.
In 2017, she launched the Children’s Society’s annual Christingle campaign to help raise £1.2 million for the UK’s most vulnerable young people over the festive period.
That same year, she joined a host of singers, including The X Factor’s Marcus Collins, to release a Christmas charity single for LGBT charity The Albert Kennedy Trust.
Brown married her first husband John Garley in 1950.
After his death she went on to marry actor Robert Arnold in 1958 and had six children with him.