Gay has been with the firm since 1988, and has been a fund manager for the past 15 years.
She was named assistant manager on the Value Trust in 2006 and worked alongside then-manager Bill Miller.
Gay took on the assistant manager of the trust, a Dublin-based version of the US strategy, in 2011.
Fund manager Peters has been with Legg Mason since 2005, when he joined the firm from Fidelity.