Jean Nyabenda, a French-speaking Burundian, told the Western Cape High Court that Novella stared at him for fifteen minutes, mimicked playing a guitar, paced up and down and danced from about 1am that morning.
"I was like maybe there is something wrong with this guy."
Novella has been charged with murdering his American marketing executive girlfriend who was found by hotel staff in the room they were sharing on the afternoon of July 29, 2015.
She had been strangled, had blunt force trauma to her face and had defensive wounds on her arms.
Nyabenda testified that he had been "astonished" when Novella stared at him while he sat behind the reception desk for about fifteen minutes: "I didn't speak to him, but all the time I was asking myself why is he staring at me like this?".
Novella had ordered a Virgin Mary, and paced up and down the reception area. Several hours later, when two other hotel staff members, Sarah and Diana, arrived for their shift, he told them Novella had not slept.
He told the court that Sarah told Novella he should get some sleep, and he replied, "'What is sleep?' He said "No I can't go and sleep, because to me sleeping is nothing".
Nyabenda said he couldn't understand why he had paid for a room, but then slept in front of the reception area on the floor: "It made me ask why is he behaving like this? It is what made me think there is something wrong with this man because of his behaviour".
"He behaved in this bizarre way over a period of some hours."
Last month, the court heard that he had taken cannabis oil and sceletium before the murder. His defence will argue diminished capacity due to drug intoxication.
Novella claims he cannot recall killing Alban and denies he had the intent to murder her.
"At the time of the said incident I was in an abnormal mental state as a result of the intake of substances. These substances had a dis-inhibiting effect on me, causing me to respond in an abnormal manner," he said in his plea statement.
Novella had brought Alban to South Africa to seek treatment for her Lyme disease at a spiritual retreat. He claims they were in love with each other and that her death "devastated" him.
Alban's parents, Howdy Kabrins and Doris Weitz, together with their respective partners, arrived in South Africa from America at the start of the trial.
They say they want to see justice done for their daughter. On Monday, they appeared to be taking strain and looked exhausted as defence lawyer William Booth began his lengthy cross-examination.
The trial continues.