In the Stark's stockade, Ser Alton and Jaime Lannister talk about Willem Frey's wedding. Ser Alton mentioned he filled in as Jaime's squire, when Bryan threw up on his horse. Jaime said it was Tyrion who made him so drunk.
In the books
In the A Song of Ice and Fire novels, there are characters name Bryan Fossoway (of the Red Apple Fossoways of Cider Hall), Bryan Frey, Bryen Caron and Bryen Farring. The captain of the guards to House Baelish is also named Bryen. There is no reference to any of them having squired for Jaime Lannister. Bryen Farring and Bryan Frey are both still young squires during the events of the series. Lord Bryen Caron and the Bryen in service to House Baelish are both older that Jaime. Bryan Fossoway is a knight during the events of the series so could potentially have squired for Jaime before the series begins.
- Bryan Fossoway at A Wiki of Ice and Fire.
- Bryan Frey at A Wiki of Ice and Fire.
- Bryen Caron at A Wiki of Ice and Fire.
- Bryan Farring at A Wiki of Ice and Fire.
- Bryen at A Wiki of Ice and Fire.