A world-renowned professional musician has denied sexually assaulting a woman while she was in a drunken sleep after they had dined together to celebrate separations from their respective partners.

Former Sydney Symphony Orchestra musician Benjamin Lawrence Jacks, 47, appeared at Downing Centre District Court on Friday on one charge of sexual intercourse without consent.

The then principal French horn player went out for dinner with the woman, who cannot be named for legal reasons, in December 2020.

The woman alleges she woke to Jacks digitally penetrating her. He has pleaded not guilty to the charge.

Crown prosecutor Rossi Kotsis showed the jury text messages in which Jacks, who has performed as guest principal with the London Symphony Orchestra and the Chicago Symphony Orchestra, apologised for the incident.

"I can't believe I woke up with your hands inside me??? Not very cool friend!! I had just spewed my guts up in your garden and was so drunk I could barely tell you my own name," the woman wrote.

Jacks replied: "My god, I'm really sorry, f***, I hope you forgive me. Not cool at all, totally correct, apart from that, it was a great night."

Woman: "Dude that was a shocker! You don't do that to a drunk friend who's crashing."

Jacks: "No I'm really sorry, I was totally hammered and not thinking straight. I feel really bad. Really terrible."

Woman: "You should feel really bad!!"

Jacks: "Anything I can do to keep this between us and to move on I would be very grateful. I feel Really sick, like Terrible, also the guilt and regret is crushing me [sic]."

Two days after the first text exchange, the woman messaged Jacks: "To be clear, what happened on Thursday morning was sexual assault".

Jacks responded: "It was a night of excess which had me acting so far out of my character that I am in a state of complete shock as to where we are. I too thought we were having dinner as friends."

Defence barrister Phillip Strickland said the pair touched each other's bodies while in bed together and the woman opened her legs, leading Jacks to believe she was consenting to sexual contact.

Further text messages sent on the morning after the incident were also shared to the jury.

The woman had ordered a ridesharing service Ola for her trip home.

"I feel very judged by the Ola," the woman texted.

Jacks: "F*** that guy, come back here, back scratch, nipple licks and coffee."

Woman: "Dude I'll be lucky if I don't puke and if Omo (her dog) hasn't weed in the house! Hope your vault is like a fricking (white box and a shush emoji)."

Jacks: "Don't worry my vault is airtight, it was a super fun night apart from the spewing, we had fun playing the piano, possibly you don't remember, I tried to look after you."

The hearing continues.