Add regression lines to a scatter matrix in Altair

Question

Is there any way to add regression lines to a scatter matrix in Altair? I am trying to add a regression line to a scatter matrix that I create with the following code :

scatter_matrix = (
    alt.Chart(movies_df)
    .mark_circle(opacity=0.5, size=10)
    .encode(
        x=alt.X(alt.repeat("column"), type="quantitative", scale=alt.Scale(zero=False)),
        y=alt.Y(alt.repeat("row"), type="quantitative", scale=alt.Scale(zero=False)),
    )
    .properties(height=120, width=120)
    .repeat(
        column=numeric_cols,
        row=numeric_cols,
        columns=5,
        title="Distribution of Numerical Columns",
    )
    .configure_axis(labels=False)
)

scatter_matrix

For a single scatter plot I can simply use .transform_regression() and layer the regression line to the base plot like so:

# create base plot
scatter_plot = alt.Chart(movies_df).mark_point().encode( 
  x="column",y="row") 
  
# add regression line
scatter_plot_line = scatter_plot + scatter_plot.transform_regression("column","row").mark_line() 

# call plot 
scatter_plot_line 

I initially tried applying this same method to the matrix but got AttributeError: 'RepeatChart' object has no attribute 'mark_line' with the code below.

scatter_matrix = (
    alt.Chart(movies_df)
    .mark_circle(opacity=0.5, size=10)
    .encode(
        x=alt.X(alt.repeat("column"), type="quantitative", scale=alt.Scale(zero=False)),
        y=alt.Y(alt.repeat("row"), type="quantitative", scale=alt.Scale(zero=False)),
    )
    .properties(height=120, width=120)
    .repeat(
        column=numeric_cols,
        row=numeric_cols,
        columns=5,
        title="Distribution of Numerical Columns",
    )
    .configure_axis(labels=False)
)

scatter_matrix_line = (
    scatter_matrix
    + scatter_matrix.transform_regression("column", "row").mark_line()
)

scatter_matrix_line 

I then tried applying the method to the base scatter matrix following .encode(), but nothing is returned at all when I call the plot. I found a source stating Altair did not yes support regression lines for plot matrices but that was dated two years ago and thought there may be a solution or workaround I could not find.

Any help is appreciated. Thanks!