The 50-year-old soap actor - who has played Kat Slater in the BBC show since 2000 - was arrested on suspicion of assaulting a police officer and disorderly conduct but released without charge.
A BBC spokesman told MailOnline: "Senior bosses have spoken to Jessie Wallace about the incident and issued a clear warning that this kind of behaviour is unacceptable. Jessie has expressed her deep regret."
Wallace was arrested in the early hours of Sunday 19 June outside Flex nightclub in Bury St Edmunds, Suffolk.
Suffolk Police said in a statement: "A 50-year-old woman was arrested early on Sunday morning in St Andrew's Street, Bury St Edmunds, on suspicion of assaulting a police officer/drunk and disorderly conduct and was released without charge after receiving a conditional caution."
The actor - who has been suspended from the soap for bad behaviour twice previously - has had issues with alcohol and drugs in the past.
She joined EastEnders in 2000 and in 2003 received a three year driving ban after pleading guilty to drink-driving.
Wallace was suspended from the soap in the mid 2000s for excessive drinking and partying which was heavily documented by the tabloid press. She also admitted to using drugs before the birth of her daughter in 2004.
Kat Slater was written out of the soap in 2005, but returned to Albert Square between 2010 and 2016.
Wallace also featured in 2017 spin-off series Kat & Alfie: Redwater with former EastEnders co-star Shane Richie, who played Kat's husband Alfie Moon.
Her character was written back into EastEnders in 2018 - when she made headlines for leaving the British Soap Awards early after reportedly arriving somewhat the-worse-for-wear.
And in January 2020 she was suspended again following an undisclosed incident that occurred on the EastEnders set.
In March this year Wallace's 17-year-old daughter Tallulah welcomed a baby boy and Wallace celebrated becoming a grandmother on social media.
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