In evidence in the Christchurch High Court today, Christine Haig said she had a brief conversation with Weatherston on January 4, 2008.
That was her birthday and she knew his 32nd birthday was on January 9.
There was a year between their ages and she jokingly suggested to him perhaps 32 was an age when it was time to grow up.
Weatherston agreed with her, saying it had been "a hard year" but said he felt good about having completed his PhD.
He told her had moved on from "a bad relationship" which Mrs Haig knew was a reference to Sophie Elliott.
He said he felt good about that and assured her the relationship was really over and he was moving on.
He wanted to do some new things like learning French and learning Salsa dancing.
And Weatherston told her Sophie had done some damage to his property and he was going to have nothing more to do with her.
She had not previously had any conversations with him about the relationship with Sophie, Mrs Haig said.
She saw him briefly a couple of times on January 9.
She had written "happy birthday" on the white board beside his door and he waved to her when he came in, sometime between 9 and 10 o'clock.
Mrs Haig said she later saw him with a young women she assumed was a marketing student in the tearoom and just before lunchtime when he was heading for the lift.
He seemed fine - "There was nothing unusual about him."
The court has heard that Weatherston stabbed Sophie to death at her Ravensbourne home about 12.30 the same day.
He admits killing her but denies committing murder.
The defence says he was lost control because of provocation from the pain of his relationship with her.
But the Crown says the number and pattern of the wounds showed a clear intention to target areas of physical beauty and attractiveness.
